diff --git a/browser.js b/browser.js
index 3e67838..2d630cf 100644
--- a/browser.js
+++ b/browser.js
@@ -5,7 +5,7 @@
 
 'use strict';
 
-var Bootstrapper = require('./lib/bootstrapper');
+const Bootstrapper = require('./lib/bootstrapper');
 
 /**
  * The browser version of `bootLoopBackApp`.
@@ -26,18 +26,18 @@ var Bootstrapper = require('./lib/bootstrapper');
 exports = module.exports = function bootBrowserApp(app, options, callback) {
   // Only using options.id to identify the browserified bundle to load for
   // this application. If no Id was provided, load the default bundle.
-  var moduleName = 'loopback-boot#instructions';
-  var appId = options && typeof options === 'object' && options.appId;
+  let moduleName = 'loopback-boot#instructions';
+  const appId = options && typeof options === 'object' && options.appId;
   if (appId)
     moduleName += '-' + appId;
 
   // The name of the module containing instructions
   // is hard-coded in lib/bundler
-  var instructions = require(moduleName);
+  const instructions = require(moduleName);
 
-  var bootstrapper = new Bootstrapper(options);
+  const bootstrapper = new Bootstrapper(options);
   bootstrapper.phases = ['starting', 'start', 'started'];
-  var context = {
+  const context = {
     app: app,
     instructions: instructions,
   };
diff --git a/index.js b/index.js
index b67e6ef..0e7f59d 100644
--- a/index.js
+++ b/index.js
@@ -6,11 +6,11 @@
 'use strict';
 
 // Strong globalize
-var g = require('./lib/globalize');
+const g = require('./lib/globalize');
 
-var PluginBase = require('./lib/plugin-base');
-var Bootstrapper = require('./lib/bootstrapper');
-var addInstructionsToBrowserify = require('./lib/bundler');
+const PluginBase = require('./lib/plugin-base');
+const Bootstrapper = require('./lib/bootstrapper');
+const addInstructionsToBrowserify = require('./lib/bundler');
 
 /**
  * Initialize an application from an options object or
@@ -158,9 +158,9 @@ exports = module.exports = function bootLoopBackApp(app, options, callback) {
   // backwards compatibility with loopback's app.boot
   options.env = options.env || app.get('env');
 
-  var bootstrapper = new Bootstrapper(options);
+  const bootstrapper = new Bootstrapper(options);
 
-  var context = {
+  const context = {
     bootstrapper: bootstrapper,
     app: app,
   };
@@ -169,9 +169,9 @@ exports = module.exports = function bootLoopBackApp(app, options, callback) {
 };
 
 exports.compile = function(options, done) {
-  var bootstrapper = new Bootstrapper(options);
+  const bootstrapper = new Bootstrapper(options);
   bootstrapper.phases = ['load', 'compile'];
-  var context = {};
+  const context = {};
   return bootstrapper.run(context, done);
 };
 
@@ -199,10 +199,10 @@ exports.Bootstrapper = Bootstrapper;
 exports.PluginBase = PluginBase;
 
 exports.execute = function(app, instructions, done) {
-  var bootstrapper = new Bootstrapper(
-    {phases: ['starting', 'start', 'started']}
+  const bootstrapper = new Bootstrapper(
+    {phases: ['starting', 'start', 'started']},
   );
-  var context = {
+  const context = {
     app: app,
     instructions: instructions,
   };
diff --git a/lib/bootstrapper.js b/lib/bootstrapper.js
index 5b3de6f..f6c2c02 100644
--- a/lib/bootstrapper.js
+++ b/lib/bootstrapper.js
@@ -5,21 +5,21 @@
 
 'use strict';
 
-var _ = require('lodash');
-var assert = require('assert');
-var async = require('async');
-var utils = require('./utils');
-var path = require('path');
-var pluginLoader = require('./plugin-loader');
-var debug = require('debug')('loopback:boot:bootstrapper');
-var Promise = require('bluebird');
-var arrayToObject = require('./utils').arrayToObject;
+const _ = require('lodash');
+const assert = require('assert');
+const async = require('async');
+const utils = require('./utils');
+const path = require('path');
+const pluginLoader = require('./plugin-loader');
+const debug = require('debug')('loopback:boot:bootstrapper');
+const Promise = require('bluebird');
+const arrayToObject = require('./utils').arrayToObject;
 
 module.exports = Bootstrapper;
 
 function createPromiseCallback() {
-  var cb;
-  var promise = new Promise(function(resolve, reject) {
+  let cb;
+  const promise = new Promise(function(resolve, reject) {
     cb = function(err, data) {
       if (err) return reject(err);
       return resolve(data);
@@ -29,22 +29,22 @@ function createPromiseCallback() {
   return cb;
 }
 
-var builtinPlugins = [
+const builtinPlugins = [
   'application', 'datasource', 'model', 'mixin',
   'middleware', 'component', 'boot-script', 'swagger',
 ];
 
-var builtinPhases = [
+const builtinPhases = [
   'load', 'compile', 'starting', 'start', 'started',
 ];
 
 function loadAndRegisterPlugins(bootstrapper, options) {
-  var loader = pluginLoader(options);
-  var loaderContext = {};
+  const loader = pluginLoader(options);
+  const loaderContext = {};
   loader.load(loaderContext);
   loader.compile(loaderContext);
 
-  for (var i in loaderContext.instructions.pluginScripts) {
+  for (const i in loaderContext.instructions.pluginScripts) {
     bootstrapper.use('/boot/' + i, loaderContext.instructions.pluginScripts[i]);
   }
 }
@@ -65,13 +65,13 @@ function Bootstrapper(options) {
   // For setting properties without modifying the original object
   options = Object.create(options);
 
-  var appRootDir = options.appRootDir = options.appRootDir || process.cwd();
-  var env = options.env || process.env.NODE_ENV || 'development';
-  var scriptExtensions = options.scriptExtensions ?
+  const appRootDir = options.appRootDir = options.appRootDir || process.cwd();
+  const env = options.env || process.env.NODE_ENV || 'development';
+  const scriptExtensions = options.scriptExtensions ?
     arrayToObject(options.scriptExtensions) :
     require.extensions;
 
-  var appConfigRootDir = options.appConfigRootDir || appRootDir;
+  const appConfigRootDir = options.appConfigRootDir || appRootDir;
 
   options.rootDir = appConfigRootDir;
   options.env = env;
@@ -84,9 +84,9 @@ function Bootstrapper(options) {
   assert(Array.isArray(this.plugins), 'Invalid plugins: ' +
     this.builtinPlugins);
 
-  var self = this;
+  const self = this;
   self.builtinPlugins.forEach(function(p) {
-    var factory = require('./plugins/' + p);
+    const factory = require('./plugins/' + p);
     self.use('/boot/' + p, factory(options));
   });
 
@@ -103,7 +103,7 @@ function Bootstrapper(options) {
  * @param {Function} handler
  */
 Bootstrapper.prototype.use = function(path, handler) {
-  var plugin = {
+  const plugin = {
     path: path,
     handler: handler,
   };
@@ -135,7 +135,7 @@ Bootstrapper.prototype.getExtensions = function(path) {
   }
   return this.plugins.filter(function(p) {
     if (p.path.indexOf(path) === -1) return false;
-    var name = p.path.substring(path.length);
+    const name = p.path.substring(path.length);
     return name && name.indexOf('/') === -1;
   });
 };
@@ -153,7 +153,7 @@ Bootstrapper.prototype.addPhases = function(phases) {
 
 function pluginIteratorFactory(context, phase) {
   return function executePluginPhase(plugin, done) {
-    var result;
+    let result;
     if (typeof plugin.handler[phase] !== 'function') {
       debug('Skipping %s.%s', plugin.handler.name, phase);
       return done();
@@ -190,24 +190,24 @@ Bootstrapper.prototype.run = function(context, done) {
   if (!done) {
     done = createPromiseCallback();
   }
-  var options = this.options;
-  var appRootDir = options.appRootDir = options.appRootDir || process.cwd();
-  var env = options.env || process.env.NODE_ENV || 'development';
+  const options = this.options;
+  const appRootDir = options.appRootDir = options.appRootDir || process.cwd();
+  const env = options.env || process.env.NODE_ENV || 'development';
 
-  var appConfigRootDir = options.appConfigRootDir || appRootDir;
+  const appConfigRootDir = options.appConfigRootDir || appRootDir;
 
   options.rootDir = appConfigRootDir;
   options.env = env;
 
   context = context || {};
 
-  var phases = context.phases || this.phases;
+  const phases = context.phases || this.phases;
 
   if (phases.includes('starting') || phases.includes('start')) {
     context.app.booting = true;
   }
 
-  var bootPlugins = this.getExtensions('/boot');
+  const bootPlugins = this.getExtensions('/boot');
   async.eachSeries(phases, function(phase, done) {
     debug('Phase %s', phase);
     async.eachSeries(bootPlugins, pluginIteratorFactory(context, phase), done);
diff --git a/lib/bundler.js b/lib/bundler.js
index 8932c6f..146c891 100644
--- a/lib/bundler.js
+++ b/lib/bundler.js
@@ -5,11 +5,11 @@
 
 'use strict';
 
-var fs = require('fs');
-var path = require('path');
-var commondir = require('commondir');
-var cloneDeep = require('lodash').cloneDeep;
-var g = require('./globalize');
+const fs = require('fs');
+const path = require('path');
+const commondir = require('commondir');
+const cloneDeep = require('lodash').cloneDeep;
+const g = require('./globalize');
 
 /**
  * Add boot instructions to a browserify bundler.
@@ -27,8 +27,8 @@ module.exports = function addInstructionsToBrowserify(context, bundler) {
 };
 
 function addPlugins(bundler) {
-  var dir = path.join(__dirname, './plugins');
-  var files = fs.readdirSync(dir);
+  const dir = path.join(__dirname, './plugins');
+  const files = fs.readdirSync(dir);
   files.forEach(function(f) {
     bundler.require(path.join(dir, f),
       {expose: './plugins/' + path.basename(f, '.js')});
@@ -36,12 +36,12 @@ function addPlugins(bundler) {
 }
 
 function bundleOtherScripts(context, bundler) {
-  var list = context.instructions.bootScripts;
+  const list = context.instructions.bootScripts;
   addScriptsToBundle('boot', list, bundler);
 }
 
 function bundlePluginScripts(context, bundler) {
-  var list = context.instructions.pluginScripts;
+  const list = context.instructions.pluginScripts;
   addScriptsToBundle('plugins', list, bundler);
 }
 
@@ -58,11 +58,11 @@ function bundleComponentScripts(context, bundler) {
 }
 
 function bundleSourceFiles(context, type, bundler) {
-  var files = context.instructions[type]
+  const files = context.instructions[type]
     .map(function(m) { return m.sourceFile; })
     .filter(function(f) { return !!f; });
 
-  var instructionToFileMapping = context.instructions[type]
+  const instructionToFileMapping = context.instructions[type]
     .map(function(m) { return files.indexOf(m.sourceFile); });
 
   addScriptsToBundle(type, files, bundler);
@@ -77,15 +77,16 @@ function bundleSourceFiles(context, type, bundler) {
 function addScriptsToBundle(name, list, bundler) {
   if (!list.length) return;
 
-  var root = commondir(list.map(path.dirname));
+  const root = commondir(list.map(path.dirname));
 
-  for (var ix in list) {
-    var filepath = list[ix];
+  for (const ix in list) {
+    const filepath = list[ix];
 
     // Build a short unique id that does not expose too much
     // information about the file system, but still preserves
     // useful information about where is the file coming from.
-    var fileid = 'loopback-boot#' + name + '#' + path.relative(root, filepath);
+    const fileid =
+      'loopback-boot#' + name + '#' + path.relative(root, filepath);
 
     // Add the file to the bundle.
     bundler.require(filepath, {expose: fileid});
@@ -97,19 +98,19 @@ function addScriptsToBundle(name, list, bundler) {
 }
 
 function bundleInstructions(context, bundler) {
-  var instructions = cloneDeep(context.instructions);
+  const instructions = cloneDeep(context.instructions);
 
-  var hasMiddleware = instructions.middleware.phases.length ||
+  const hasMiddleware = instructions.middleware.phases.length ||
     instructions.middleware.middleware.length;
   if (hasMiddleware) {
     g.warn(
       'Discarding {{middleware}} instructions,' +
-      ' {{loopback}} client does not support {{middleware}}.'
+      ' {{loopback}} client does not support {{middleware}}.',
     );
   }
   delete instructions.middleware;
 
-  var instructionsString = JSON.stringify(instructions, null, 2);
+  const instructionsString = JSON.stringify(instructions, null, 2);
 
   /* The following code does not work due to a bug in browserify
    * https://github.com/substack/node-browserify/issues/771
@@ -119,7 +120,7 @@ function bundleInstructions(context, bundler) {
    b.require(instructionsStream, { expose: 'loopback-boot#instructions' });
    */
 
-  var instructionId = 'instructions';
+  let instructionId = 'instructions';
   // Create an unique instruction identifier using the application ID.
   // This is only useful when multiple loopback applications are being bundled
   // together.
@@ -128,10 +129,10 @@ function bundleInstructions(context, bundler) {
 
   // Write the instructions to a file in our node_modules folder.
   // The location should not really matter as long as it is .gitignore-ed
-  var instructionsFile = path.resolve(__dirname,
+  const instructionsFile = path.resolve(__dirname,
     '..', 'generated-' + instructionId + '.json');
   fs.writeFileSync(instructionsFile, instructionsString, 'utf-8');
 
-  var moduleName = 'loopback-boot#' + instructionId;
+  const moduleName = 'loopback-boot#' + instructionId;
   bundler.require(instructionsFile, {expose: moduleName});
 }
diff --git a/lib/globalize.js b/lib/globalize.js
index 64bdf32..3dabea9 100644
--- a/lib/globalize.js
+++ b/lib/globalize.js
@@ -5,7 +5,7 @@
 
 'use strict';
 
-var path = require('path');
-var SG = require('strong-globalize');
+const path = require('path');
+const SG = require('strong-globalize');
 SG.SetRootDir(path.join(__dirname, '..'), {autonomousMsgLoading: 'all'});
 module.exports = SG();
diff --git a/lib/plugin-base.js b/lib/plugin-base.js
index 9138427..b17a3bc 100644
--- a/lib/plugin-base.js
+++ b/lib/plugin-base.js
@@ -5,13 +5,13 @@
 
 'use strict';
 
-var fs = require('fs');
-var path = require('path');
-var debug = require('debug')('loopback:boot:plugin');
-var assert = require('assert');
-var _ = require('lodash');
-var util = require('./utils');
-var g = require('./globalize');
+const fs = require('fs');
+const path = require('path');
+const debug = require('debug')('loopback:boot:plugin');
+const assert = require('assert');
+const _ = require('lodash');
+const util = require('./utils');
+const g = require('./globalize');
 
 module.exports = PluginBase;
 
@@ -26,11 +26,11 @@ PluginBase.prototype.getRootDir = function() {
 };
 
 PluginBase.prototype.load = function(context) {
-  var rootDir = this.getRootDir() || this.options.rootDir;
-  var env = this.options.env;
+  const rootDir = this.getRootDir() || this.options.rootDir;
+  const env = this.options.env;
   assert(this.name, 'Plugin name must to be set');
   debug('Root dir: %s, env: %s, artifact: %s', rootDir, env, this.artifact);
-  var config = {};
+  let config = {};
   if (this.options[this.name]) {
     // First check if options have the corresponding config object
     debug('Artifact: %s is using provided config obj instead' +
@@ -67,7 +67,7 @@ PluginBase.prototype.merge = function(target, config, keyPrefix) {
  * @returns {Object}
  */
 PluginBase.prototype.loadNamed = function(rootDir, env, name) {
-  var files = this.findConfigFiles(rootDir, env, name);
+  const files = this.findConfigFiles(rootDir, env, name);
   debug('Looking in dir %s for %s configs', rootDir, this.name);
   if (files.length) {
     debug('found %s %s files: %j', env, name, files);
@@ -75,8 +75,8 @@ PluginBase.prototype.loadNamed = function(rootDir, env, name) {
       debug('  %s', f);
     });
   }
-  var configs = this._loadConfigFiles(files);
-  var merged = this._mergeConfigurations(configs);
+  const configs = this._loadConfigFiles(files);
+  const merged = this._mergeConfigurations(configs);
 
   debug('merged %s %s configuration %j', env, name, merged);
 
@@ -92,14 +92,14 @@ PluginBase.prototype.loadNamed = function(rootDir, env, name) {
  * @returns {Array.<String>} Array of absolute file paths.
  */
 PluginBase.prototype.findConfigFiles = function(rootDir, env, name, exts) {
-  var master = ifExists(name + '.json');
+  const master = ifExists(name + '.json');
   if (!master && (ifExistsWithAnyExt(name + '.local') ||
     ifExistsWithAnyExt(name + '.' + env))) {
     g.warn('WARNING: Main config file "%s{{.json}}" is missing', name);
   }
   if (!master) return [];
 
-  var candidates = [
+  const candidates = [
     master,
     ifExistsWithAnyExt(name + '.local'),
     ifExistsWithAnyExt(name + '.' + env),
@@ -110,14 +110,14 @@ PluginBase.prototype.findConfigFiles = function(rootDir, env, name, exts) {
   });
 
   function ifExists(fileName) {
-    var filePath = path.resolve(rootDir, fileName);
+    const filePath = path.resolve(rootDir, fileName);
     return util.fileExistsSync(filePath) ? filePath : undefined;
   }
 
   function ifExistsWithAnyExt(fileName) {
-    var extensions = exts || ['js', 'json'];
-    var file;
-    for (var i = 0, n = extensions.length; i < n; i++) {
+    const extensions = exts || ['js', 'json'];
+    let file;
+    for (let i = 0, n = extensions.length; i < n; i++) {
       file = ifExists(fileName + '.' + extensions[i]);
       if (file) {
         return file;
@@ -134,7 +134,7 @@ PluginBase.prototype.findConfigFiles = function(rootDir, env, name, exts) {
  */
 PluginBase.prototype._loadConfigFiles = function(files) {
   return files.map(function(f) {
-    var config = require(f);
+    let config = require(f);
     config = _.cloneDeep(config);
     Object.defineProperty(config, '_filename', {
       enumerable: false,
@@ -149,18 +149,18 @@ PluginBase.prototype._loadConfigFiles = function(files) {
  * @param {Array.<Object>} configObjects
  */
 PluginBase.prototype._mergeConfigurations = function(configObjects) {
-  var result = configObjects.shift() || {};
+  const result = configObjects.shift() || {};
   while (configObjects.length) {
-    var next = configObjects.shift();
+    const next = configObjects.shift();
     this.merge(result, next, next._filename);
   }
   return result;
 };
 
 PluginBase.prototype._mergeObjects = function(target, config, keyPrefix) {
-  for (var key in config) {
-    var fullKey = keyPrefix ? keyPrefix + '.' + key : key;
-    var err = this._mergeSingleItemOrProperty(target, config, key, fullKey);
+  for (const key in config) {
+    const fullKey = keyPrefix ? keyPrefix + '.' + key : key;
+    const err = this._mergeSingleItemOrProperty(target, config, key, fullKey);
     if (err) throw err;
   }
   return null; // no error
@@ -170,12 +170,12 @@ PluginBase.prototype._mergeNamedItems = function(arr1, arr2, key) {
   assert(Array.isArray(arr1), 'invalid array: ' + arr1);
   assert(Array.isArray(arr2), 'invalid array: ' + arr2);
   key = key || 'name';
-  var result = [].concat(arr1);
-  for (var i = 0, n = arr2.length; i < n; i++) {
-    var item = arr2[i];
-    var found = false;
+  const result = [].concat(arr1);
+  for (let i = 0, n = arr2.length; i < n; i++) {
+    const item = arr2[i];
+    let found = false;
     if (item[key]) {
-      for (var j = 0, k = result.length; j < k; j++) {
+      for (let j = 0, k = result.length; j < k; j++) {
         if (result[j][key] === item[key]) {
           this._mergeObjects(result[j], item);
           found = true;
@@ -192,8 +192,8 @@ PluginBase.prototype._mergeNamedItems = function(arr1, arr2, key) {
 
 PluginBase.prototype._mergeSingleItemOrProperty =
   function(target, config, key, fullKey) {
-    var origValue = target[key];
-    var newValue = config[key];
+    const origValue = target[key];
+    const newValue = config[key];
 
     if (!hasCompatibleType(origValue, newValue)) {
       return 'Cannot merge values of incompatible types for the option `' +
@@ -219,9 +219,9 @@ PluginBase.prototype._mergeArrays = function(target, config, keyPrefix) {
   }
 
   // Use for(;;) to iterate over undefined items, for(in) would skip them.
-  for (var ix = 0; ix < target.length; ix++) {
-    var fullKey = keyPrefix + '[' + ix + ']';
-    var err = this._mergeSingleItemOrProperty(target, config, ix, fullKey);
+  for (let ix = 0; ix < target.length; ix++) {
+    const fullKey = keyPrefix + '[' + ix + ']';
+    const err = this._mergeSingleItemOrProperty(target, config, ix, fullKey);
     if (err) return err;
   }
 
@@ -244,10 +244,10 @@ function hasCompatibleType(origValue, newValue) {
 }
 
 PluginBase.prototype.compile = function(context) {
-  var instructions;
+  let instructions;
   if (typeof this.buildInstructions === 'function') {
-    var rootDir = this.options.rootDir;
-    var config = context.configurations[this.name] || {};
+    const rootDir = this.options.rootDir;
+    const config = context.configurations[this.name] || {};
     instructions = this.buildInstructions(context, rootDir, config);
   } else {
     instructions = context.configurations[this.name];
@@ -265,12 +265,12 @@ PluginBase.prototype.compile = function(context) {
   return undefined;
 };
 
-var DYNAMIC_CONFIG_PARAM = /\$\{(\w+)\}$/;
+const DYNAMIC_CONFIG_PARAM = /\$\{(\w+)\}$/;
 function getConfigVariable(app, param, useEnvVars) {
-  var configVariable = param;
-  var match = configVariable.match(DYNAMIC_CONFIG_PARAM);
+  let configVariable = param;
+  const match = configVariable.match(DYNAMIC_CONFIG_PARAM);
   if (match) {
-    var varName = match[1];
+    const varName = match[1];
     if (useEnvVars && process.env[varName] !== undefined) {
       debug('Dynamic Configuration: Resolved via process.env: %s as %s',
         process.env[varName], param);
@@ -278,7 +278,7 @@ function getConfigVariable(app, param, useEnvVars) {
     } else if (app.get(varName) !== undefined) {
       debug('Dynamic Configuration: Resolved via app.get(): %s as %s',
         app.get(varName), param);
-      var appValue = app.get(varName);
+      const appValue = app.get(varName);
       configVariable = appValue;
     } else {
       // previously it returns the original string such as "${restApiRoot}"
@@ -296,8 +296,8 @@ function getConfigVariable(app, param, useEnvVars) {
 }
 
 PluginBase.prototype.getUpdatedConfigObject = function(context, config, opts) {
-  var app = context.app;
-  var useEnvVars = opts && opts.useEnvVars;
+  const app = context.app;
+  const useEnvVars = opts && opts.useEnvVars;
 
   function interpolateVariables(config) {
     // config is a string and contains a config variable ('${var}')
@@ -317,9 +317,9 @@ PluginBase.prototype.getUpdatedConfigObject = function(context, config, opts) {
       return config;
 
     // recurse into object props
-    var interpolated = {};
+    const interpolated = {};
     Object.keys(config).forEach(function(configKey) {
-      var value = config[configKey];
+      const value = config[configKey];
       if (Array.isArray(value)) {
         interpolated[configKey] = value.map(interpolateVariables);
       } else if (typeof value === 'string') {
diff --git a/lib/plugin-loader.js b/lib/plugin-loader.js
index bc01d36..1fec706 100644
--- a/lib/plugin-loader.js
+++ b/lib/plugin-loader.js
@@ -5,13 +5,13 @@
 
 'use strict';
 
-var util = require('util');
-var utils = require('./utils');
-var path = require('path');
-var async = require('async');
-var debug = require('debug')('loopback:boot:plugin-loader');
-var PluginBase = require('./plugin-base');
-var _ = require('lodash');
+const util = require('util');
+const utils = require('./utils');
+const path = require('path');
+const async = require('async');
+const debug = require('debug')('loopback:boot:plugin-loader');
+const PluginBase = require('./plugin-base');
+const _ = require('lodash');
 
 module.exports = function(options) {
   return new PluginScript(options);
@@ -24,23 +24,23 @@ function PluginScript(options) {
 util.inherits(PluginScript, PluginBase);
 
 PluginScript.prototype.load = function(context) {
-  var options = this.options;
-  var appRootDir = options.rootDir;
+  const options = this.options;
+  const appRootDir = options.rootDir;
   // require directories
-  var pluginDirs = options.pluginDirs || []; // precedence
+  let pluginDirs = options.pluginDirs || []; // precedence
   pluginDirs = pluginDirs.concat(path.join(appRootDir, 'plugins'));
   utils.resolveRelativePaths(pluginDirs, appRootDir);
 
-  var pluginScripts = options.pluginScripts || [];
+  let pluginScripts = options.pluginScripts || [];
   utils.resolveRelativePaths(pluginScripts, appRootDir);
 
   pluginDirs.forEach(function(dir) {
     pluginScripts = pluginScripts.concat(
-      utils.findScripts(dir, options.scriptExtensions)
+      utils.findScripts(dir, options.scriptExtensions),
     );
-    var envdir = dir + '/' + options.env;
+    const envdir = dir + '/' + options.env;
     pluginScripts = pluginScripts.concat(
-      utils.findScripts(envdir, options.scriptExtensions)
+      utils.findScripts(envdir, options.scriptExtensions),
     );
   });
 
@@ -51,15 +51,15 @@ PluginScript.prototype.load = function(context) {
 };
 
 PluginScript.prototype.compile = function(context) {
-  var pluginScripts = context.configurations.pluginScripts;
+  const pluginScripts = context.configurations.pluginScripts;
   context.instructions = context.instructions || {};
-  var plugins = context.instructions.pluginScripts = {};
-  var self = this;
+  const plugins = context.instructions.pluginScripts = {};
+  const self = this;
   pluginScripts.forEach(function(ps) {
     debug('Loading %s', ps);
-    var factory = require(ps);
-    var handler = factory(self.options);
-    var name = handler.name || path.basename(ps, '.js');
+    const factory = require(ps);
+    const handler = factory(self.options);
+    const name = handler.name || path.basename(ps, '.js');
     debug('Loaded plugin name: %s', name);
     plugins[name] = handler;
   });
diff --git a/lib/plugins/application.js b/lib/plugins/application.js
index 46f56bc..5779b2c 100644
--- a/lib/plugins/application.js
+++ b/lib/plugins/application.js
@@ -5,11 +5,11 @@
 
 'use strict';
 
-var util = require('util');
-var assert = require('assert');
-var semver = require('semver');
-var PluginBase = require('../plugin-base');
-var g = require('../globalize');
+const util = require('util');
+const assert = require('assert');
+const semver = require('semver');
+const PluginBase = require('../plugin-base');
+const g = require('../globalize');
 
 module.exports = function(options) {
   return new Application(options);
@@ -22,19 +22,19 @@ function Application(options) {
 util.inherits(Application, PluginBase);
 
 function assertLoopBackVersion(app) {
-  var RANGE = '2.x || 3.x';
+  const RANGE = '2.x || 3.x';
 
-  var loopback = app.loopback;
+  const loopback = app.loopback;
   // remove any pre-release tag from the version string,
   // because semver has special treatment of pre-release versions,
   // while loopback-boot treats pre-releases the same way as regular versions
-  var version = (loopback.version || '1.0.0').replace(/-.*$/, '');
+  const version = (loopback.version || '1.0.0').replace(/-.*$/, '');
   if (!semver.satisfies(version, RANGE)) {
-    var msg = g.f(
+    const msg = g.f(
       'The `app` is powered by an incompatible loopback version %s. ' +
       'Supported versions: %s',
       loopback.version || '(unknown)',
-      RANGE
+      RANGE,
     );
     throw new Error(msg);
   }
@@ -47,7 +47,7 @@ function setEnv(app, env) {
 
 function setHost(app, appConfig) {
   // jscs:disable requireCamelCaseOrUpperCaseIdentifiers
-  var host =
+  const host =
     process.env.npm_config_host ||
     process.env.OPENSHIFT_SLS_IP ||
     process.env.OPENSHIFT_NODEJS_IP ||
@@ -65,7 +65,7 @@ function setHost(app, appConfig) {
 
 function setPort(app, appConfig) {
   // jscs:disable requireCamelCaseOrUpperCaseIdentifiers
-  var port = find([
+  const port = find([
     process.env.npm_config_port,
     process.env.OPENSHIFT_SLS_PORT,
     process.env.OPENSHIFT_NODEJS_PORT,
@@ -80,7 +80,7 @@ function setPort(app, appConfig) {
   });
 
   if (port !== undefined) {
-    var portType = typeof port;
+    const portType = typeof port;
     assert(portType === 'string' || portType === 'number',
       'app.port must be a string or number');
     app.set('port', port);
@@ -92,7 +92,7 @@ function find(array, predicate) {
 }
 
 function setApiRoot(app, appConfig) {
-  var restApiRoot =
+  const restApiRoot =
     appConfig.restApiRoot ||
     app.get('restApiRoot') ||
     '/api';
@@ -106,8 +106,8 @@ function setApiRoot(app, appConfig) {
 }
 
 function applyAppConfig(app, appConfig) {
-  for (var configKey in appConfig) {
-    var cur = app.get(configKey);
+  for (const configKey in appConfig) {
+    const cur = app.get(configKey);
     if (cur === undefined || cur === null) {
       app.set(configKey, appConfig[configKey]);
     }
@@ -115,10 +115,10 @@ function applyAppConfig(app, appConfig) {
 }
 
 Application.prototype.starting = function(context) {
-  var app = context.app;
+  const app = context.app;
   assertLoopBackVersion(app);
 
-  var appConfig = context.instructions.application;
+  const appConfig = context.instructions.application;
   setEnv(app, context.instructions.env || this.options.env);
   setHost(app, appConfig);
   setPort(app, appConfig);
@@ -127,7 +127,7 @@ Application.prototype.starting = function(context) {
 };
 
 Application.prototype.started = function(context, done) {
-  var app = context.app;
+  const app = context.app;
   process.nextTick(function() {
     app.emit('booted');
     done();
diff --git a/lib/plugins/boot-script.js b/lib/plugins/boot-script.js
index a0eb80c..ce54926 100644
--- a/lib/plugins/boot-script.js
+++ b/lib/plugins/boot-script.js
@@ -5,14 +5,14 @@
 
 'use strict';
 
-var util = require('util');
-var utils = require('../utils');
-var path = require('path');
-var async = require('async');
-var debug = require('debug')('loopback:boot:script');
-var PluginBase = require('../plugin-base');
-var _ = require('lodash');
-var g = require('../globalize');
+const util = require('util');
+const utils = require('../utils');
+const path = require('path');
+const async = require('async');
+const debug = require('debug')('loopback:boot:script');
+const PluginBase = require('../plugin-base');
+const _ = require('lodash');
+const g = require('../globalize');
 
 module.exports = function(options) {
   return new Script(options);
@@ -25,23 +25,23 @@ function Script(options) {
 util.inherits(Script, PluginBase);
 
 Script.prototype.load = function(context) {
-  var options = this.options;
-  var appRootDir = options.rootDir;
+  const options = this.options;
+  const appRootDir = options.rootDir;
   // require directories
-  var bootDirs = options.bootDirs || []; // precedence
+  let bootDirs = options.bootDirs || []; // precedence
   bootDirs = bootDirs.concat(path.join(appRootDir, 'boot'));
   utils.resolveRelativePaths(bootDirs, appRootDir);
 
-  var bootScripts = options.bootScripts || [];
+  let bootScripts = options.bootScripts || [];
   utils.resolveRelativePaths(bootScripts, appRootDir);
 
   bootDirs.forEach(function(dir) {
     bootScripts = bootScripts.concat(
-      utils.findScripts(dir, options.scriptExtensions)
+      utils.findScripts(dir, options.scriptExtensions),
     );
-    var envdir = dir + '/' + options.env;
+    const envdir = dir + '/' + options.env;
     bootScripts = bootScripts.concat(
-      utils.findScripts(envdir, options.scriptExtensions)
+      utils.findScripts(envdir, options.scriptExtensions),
     );
   });
 
@@ -54,18 +54,18 @@ Script.prototype.load = function(context) {
 };
 
 Script.prototype.start = function(context, done) {
-  var app = context.app;
-  var instructions = context.instructions[this.name];
+  const app = context.app;
+  const instructions = context.instructions[this.name];
   runScripts(app, instructions, done);
 };
 
 function runScripts(app, list, callback) {
   list = list || [];
-  var functions = [];
+  const functions = [];
   list.forEach(function(filepath) {
     debug('Requiring script %s', filepath);
     try {
-      var exports = require(filepath);
+      let exports = require(filepath);
       if (exports.__esModule) exports = exports.default;
       if (typeof exports === 'function') {
         debug('Exported function detected %s', filepath);
@@ -82,7 +82,7 @@ function runScripts(app, list, callback) {
 
   async.eachSeries(functions, function(f, done) {
     debug('Running script %s', f.path);
-    var cb = function(err) {
+    let cb = function(err) {
       debug('Async function %s %s', err ? 'failed' : 'finished', f.path);
       done(err);
       // Make sure done() isn't called twice, e.g. if a script returns a
@@ -90,7 +90,7 @@ function runScripts(app, list, callback) {
       cb = function() {};
     };
     try {
-      var result = f.func(app, cb);
+      const result = f.func(app, cb);
       if (result && typeof result.then === 'function') {
         result.then(function() { cb(); }, cb);
       } else if (f.func.length < 2) {
diff --git a/lib/plugins/component.js b/lib/plugins/component.js
index 9d4c722..7a49795 100644
--- a/lib/plugins/component.js
+++ b/lib/plugins/component.js
@@ -5,13 +5,13 @@
 
 'use strict';
 
-var util = require('util');
-var debug = require('debug')('loopback:boot:component');
-var PluginBase = require('../plugin-base');
+const util = require('util');
+const debug = require('debug')('loopback:boot:component');
+const PluginBase = require('../plugin-base');
 
-var utils = require('../utils');
+const utils = require('../utils');
 
-var resolveAppScriptPath = utils.resolveAppScriptPath;
+const resolveAppScriptPath = utils.resolveAppScriptPath;
 
 module.exports = function(options) {
   return new Component(options);
@@ -40,11 +40,11 @@ Component.prototype.buildInstructions = function(context, rootDir, config) {
 };
 
 Component.prototype.start = function(context) {
-  var app = context.app;
-  var self = this;
+  const app = context.app;
+  const self = this;
   context.instructions[this.name].forEach(function(data) {
     debug('Configuring component %j', data.sourceFile);
-    var configFn = require(data.sourceFile);
+    const configFn = require(data.sourceFile);
     data.config = self.getUpdatedConfigObject(context, data.config,
       {useEnvVars: true});
     configFn(app, data.config);
diff --git a/lib/plugins/datasource.js b/lib/plugins/datasource.js
index 62ccdd1..bfcdede 100644
--- a/lib/plugins/datasource.js
+++ b/lib/plugins/datasource.js
@@ -5,10 +5,10 @@
 
 'use strict';
 
-var util = require('util');
-var utils = require('../utils');
-var PluginBase = require('../plugin-base');
-var debug = require('debug')('loopback:boot:datasource');
+const util = require('util');
+const utils = require('../utils');
+const PluginBase = require('../plugin-base');
+const debug = require('debug')('loopback:boot:datasource');
 
 module.exports = function(options) {
   return new DataSource(options);
@@ -25,9 +25,9 @@ DataSource.prototype.getRootDir = function() {
 };
 
 DataSource.prototype.start = function(context) {
-  var app = context.app;
-  var self = this;
-  var lazyConnect = process.env.LB_LAZYCONNECT_DATASOURCES;
+  const app = context.app;
+  const self = this;
+  const lazyConnect = process.env.LB_LAZYCONNECT_DATASOURCES;
   utils.forEachKeyedObject(context.instructions[this.name], function(key, obj) {
     obj = self.getUpdatedConfigObject(context, obj, {useEnvVars: true});
     debug('Registering data source %s %j', key, obj);
diff --git a/lib/plugins/middleware.js b/lib/plugins/middleware.js
index 25e4c52..858eb47 100644
--- a/lib/plugins/middleware.js
+++ b/lib/plugins/middleware.js
@@ -5,18 +5,18 @@
 
 'use strict';
 
-var util = require('util');
-var assert = require('assert');
-var path = require('path');
-var _ = require('lodash');
-var cloneDeepWith = _.cloneDeepWith;
-var cloneDeep = _.cloneDeep;
-var debug = require('debug')('loopback:boot:middleware');
-var PluginBase = require('../plugin-base');
-var utils = require('../utils');
-var g = require('../globalize');
+const util = require('util');
+const assert = require('assert');
+const path = require('path');
+const _ = require('lodash');
+const cloneDeepWith = _.cloneDeepWith;
+const cloneDeep = _.cloneDeep;
+const debug = require('debug')('loopback:boot:middleware');
+const PluginBase = require('../plugin-base');
+const utils = require('../utils');
+const g = require('../globalize');
 
-var resolveAppScriptPath = utils.resolveAppScriptPath;
+const resolveAppScriptPath = utils.resolveAppScriptPath;
 
 module.exports = function(options) {
   return new Middleware(options);
@@ -33,7 +33,7 @@ Middleware.prototype.getRootDir = function() {
 };
 
 Middleware.prototype.merge = function(target, config, fileName) {
-  var err, phase;
+  let err, phase;
   for (phase in config) {
     if (phase in target) {
       err = this.mergePhaseConfig(target[phase], config[phase], phase);
@@ -46,11 +46,11 @@ Middleware.prototype.merge = function(target, config, fileName) {
 };
 
 Middleware.prototype.mergePhaseConfig = function(target, config, phase) {
-  var err, mw;
+  let err, mw;
   for (mw in config) {
     if (mw in target) {
-      var targetMiddleware = target[mw];
-      var configMiddleware = config[mw];
+      const targetMiddleware = target[mw];
+      const configMiddleware = config[mw];
       if (Array.isArray(targetMiddleware) && Array.isArray(configMiddleware)) {
         // Both are arrays, combine them
         target[mw] = this._mergeNamedItems(targetMiddleware, configMiddleware);
@@ -83,18 +83,18 @@ Middleware.prototype.mergePhaseConfig = function(target, config, phase) {
 };
 
 Middleware.prototype.buildInstructions = function(context, rootDir, config) {
-  var phasesNames = Object.keys(config);
-  var middlewareList = [];
+  const phasesNames = Object.keys(config);
+  const middlewareList = [];
 
   phasesNames.forEach(function(phase) {
-    var phaseConfig = config[phase];
+    const phaseConfig = config[phase];
     Object.keys(phaseConfig).forEach(function(middleware) {
-      var allConfigs = phaseConfig[middleware];
+      let allConfigs = phaseConfig[middleware];
       if (!Array.isArray(allConfigs))
         allConfigs = [allConfigs];
 
       allConfigs.forEach(function(config) {
-        var resolved = resolveMiddlewarePath(rootDir, middleware, config);
+        const resolved = resolveMiddlewarePath(rootDir, middleware, config);
         // resolved.sourceFile will be false-y if an optional middleware
         // is not resolvable.
         // if a non-optional middleware is not resolvable, it will throw
@@ -105,16 +105,16 @@ Middleware.prototype.buildInstructions = function(context, rootDir, config) {
             resolved.optional);
         }
 
-        var middlewareConfig = cloneDeep(config);
+        const middlewareConfig = cloneDeep(config);
         middlewareConfig.phase = phase;
 
         if (middlewareConfig.params) {
           middlewareConfig.params = resolveMiddlewareParams(
-            rootDir, middlewareConfig.params
+            rootDir, middlewareConfig.params,
           );
         }
 
-        var item = {
+        const item = {
           sourceFile: resolved.sourceFile,
           config: middlewareConfig,
         };
@@ -126,7 +126,7 @@ Middleware.prototype.buildInstructions = function(context, rootDir, config) {
     });
   });
 
-  var flattenedPhaseNames = phasesNames
+  const flattenedPhaseNames = phasesNames
     .map(function getBaseName(name) {
       return name.replace(/:[^:]+$/, '');
     })
@@ -143,15 +143,15 @@ Middleware.prototype.buildInstructions = function(context, rootDir, config) {
 };
 
 function resolveMiddlewarePath(rootDir, middleware, config) {
-  var resolved = {
+  const resolved = {
     optional: !!config.optional,
   };
 
-  var segments = middleware.split('#');
-  var pathName = segments[0];
-  var fragment = segments[1];
-  var middlewarePath = pathName;
-  var opts = {
+  const segments = middleware.split('#');
+  let pathName = segments[0];
+  const fragment = segments[1];
+  const middlewarePath = pathName;
+  const opts = {
     strict: true,
     optional: !!config.optional,
   };
@@ -165,7 +165,7 @@ function resolveMiddlewarePath(rootDir, middleware, config) {
     pathName = path.resolve(rootDir, pathName);
   }
 
-  var resolveOpts = _.extend(opts, {
+  const resolveOpts = _.extend(opts, {
     // Workaround for strong-agent to allow probes to detect that
     // strong-express-middleware was loaded: exclude the path to the
     // module main file from the source file path.
@@ -175,7 +175,7 @@ function resolveMiddlewarePath(rootDir, middleware, config) {
     //   node_modules/strong-express-metrics/index.js
     fullResolve: false,
   });
-  var sourceFile = resolveAppScriptPath(rootDir, middlewarePath, resolveOpts);
+  const sourceFile = resolveAppScriptPath(rootDir, middlewarePath, resolveOpts);
 
   if (!fragment) {
     resolved.sourceFile = sourceFile;
@@ -184,7 +184,7 @@ function resolveMiddlewarePath(rootDir, middleware, config) {
 
   // Try to require the module and check if <module>.<fragment> is a valid
   // function
-  var m = require(sourceFile);
+  const m = require(sourceFile);
   if (typeof m[fragment] === 'function') {
     resolved.sourceFile = sourceFile;
     return resolved;
@@ -194,7 +194,7 @@ function resolveMiddlewarePath(rootDir, middleware, config) {
    * module/server/middleware/fragment
    * module/middleware/fragment
    */
-  var candidates = [
+  const candidates = [
     pathName + '/server/middleware/' + fragment,
     pathName + '/middleware/' + fragment,
     // TODO: [rfeng] Should we support the following flavors?
@@ -202,7 +202,7 @@ function resolveMiddlewarePath(rootDir, middleware, config) {
     // pathName + '/' + fragment
   ];
 
-  var err, ix;
+  let err, ix;
   for (ix in candidates) {
     try {
       resolved.sourceFile = resolveAppScriptPath(rootDir, candidates[ix], opts);
@@ -217,7 +217,7 @@ function resolveMiddlewarePath(rootDir, middleware, config) {
 }
 
 // Match values starting with `$!./` or `$!../`
-var MIDDLEWARE_PATH_PARAM_REGEX = /^\$!(\.\/|\.\.\/)/;
+const MIDDLEWARE_PATH_PARAM_REGEX = /^\$!(\.\/|\.\.\/)/;
 
 function resolveMiddlewareParams(rootDir, params) {
   return cloneDeepWith(params, function resolvePathParam(value) {
@@ -230,20 +230,20 @@ function resolveMiddlewareParams(rootDir, params) {
 }
 
 Middleware.prototype.start = function(context) {
-  var self = this;
-  var app = context.app;
-  var instructions = context.instructions.middleware;
+  const self = this;
+  const app = context.app;
+  const instructions = context.instructions.middleware;
   if (!instructions) {
     // the browserified client does not support middleware
     return;
   }
 
   // Phases can be empty
-  var phases = instructions.phases || [];
+  const phases = instructions.phases || [];
   assert(Array.isArray(phases),
     'Middleware phases must be an array');
 
-  var middleware = instructions.middleware;
+  const middleware = instructions.middleware;
   assert(Array.isArray(middleware),
     'Middleware must be an array');
 
@@ -253,7 +253,7 @@ Middleware.prototype.start = function(context) {
   middleware.forEach(function(data) {
     debug('Configuring middleware %j%s', data.sourceFile,
       data.fragment ? ('#' + data.fragment) : '');
-    var factory = require(data.sourceFile);
+    let factory = require(data.sourceFile);
     if (data.fragment) {
       factory = factory[data.fragment].bind(factory);
     }
diff --git a/lib/plugins/mixin.js b/lib/plugins/mixin.js
index f828899..f2c17b5 100644
--- a/lib/plugins/mixin.js
+++ b/lib/plugins/mixin.js
@@ -5,19 +5,19 @@
 
 'use strict';
 
-var util = require('util');
-var fs = require('fs');
-var path = require('path');
-var PluginBase = require('../plugin-base');
-var _ = require('lodash');
-var debug = require('debug')('loopback:boot:mixin');
-var utils = require('../utils');
-var g = require('../globalize');
+const util = require('util');
+const fs = require('fs');
+const path = require('path');
+const PluginBase = require('../plugin-base');
+const _ = require('lodash');
+const debug = require('debug')('loopback:boot:mixin');
+const utils = require('../utils');
+const g = require('../globalize');
 
-var tryResolveAppPath = utils.tryResolveAppPath;
-var getExcludedExtensions = utils.getExcludedExtensions;
-var findScripts = utils.findScripts;
-var FILE_EXTENSION_JSON = utils.FILE_EXTENSION_JSON;
+const tryResolveAppPath = utils.tryResolveAppPath;
+const getExcludedExtensions = utils.getExcludedExtensions;
+const findScripts = utils.findScripts;
+const FILE_EXTENSION_JSON = utils.FILE_EXTENSION_JSON;
 
 module.exports = function(options) {
   return new Mixin(options);
@@ -30,14 +30,14 @@ function Mixin(options) {
 util.inherits(Mixin, PluginBase);
 
 Mixin.prototype.buildInstructions = function(context, rootDir, config) {
-  var modelsMeta = context.configurations.mixins._meta || {};
-  var modelInstructions = context.instructions.models;
-  var mixinSources = this.options.mixinSources || modelsMeta.mixins ||
+  const modelsMeta = context.configurations.mixins._meta || {};
+  const modelInstructions = context.instructions.models;
+  const mixinSources = this.options.mixinSources || modelsMeta.mixins ||
     ['./mixins'];
-  var scriptExtensions = this.options.scriptExtensions || require.extensions;
+  const scriptExtensions = this.options.scriptExtensions || require.extensions;
 
-  var mixinInstructions = buildAllMixinInstructions(
-    rootDir, this.options, mixinSources, scriptExtensions, modelInstructions
+  const mixinInstructions = buildAllMixinInstructions(
+    rootDir, this.options, mixinSources, scriptExtensions, modelInstructions,
   );
 
   return mixinInstructions;
@@ -46,14 +46,14 @@ Mixin.prototype.buildInstructions = function(context, rootDir, config) {
 function buildAllMixinInstructions(appRootDir, options, mixinSources,
   scriptExtensions, modelInstructions) {
   // load mixins from `options.mixins`
-  var sourceFiles = options.mixins || [];
-  var mixinDirs = options.mixinDirs || [];
-  var instructionsFromMixins = loadMixins(sourceFiles, options.normalization);
+  let sourceFiles = options.mixins || [];
+  const mixinDirs = options.mixinDirs || [];
+  const instructionsFromMixins = loadMixins(sourceFiles, options.normalization);
 
   // load mixins from `options.mixinDirs`
   sourceFiles = findMixinDefinitions(appRootDir, mixinDirs, scriptExtensions);
   if (sourceFiles === undefined) return;
-  var instructionsFromMixinDirs = loadMixins(sourceFiles,
+  const instructionsFromMixinDirs = loadMixins(sourceFiles,
     options.normalization);
 
   /* If `mixinDirs` and `mixinSources` have any directories in common,
@@ -64,31 +64,31 @@ function buildAllMixinInstructions(appRootDir, options, mixinSources,
   sourceFiles = findMixinDefinitions(appRootDir, mixinSources,
     scriptExtensions);
   if (sourceFiles === undefined) return;
-  var instructionsFromMixinSources = loadMixins(sourceFiles,
+  let instructionsFromMixinSources = loadMixins(sourceFiles,
     options.normalization);
 
   // Fetch unique list of mixin names, used in models
-  var modelMixins = fetchMixinNamesUsedInModelInstructions(modelInstructions);
+  let modelMixins = fetchMixinNamesUsedInModelInstructions(modelInstructions);
   modelMixins = _.uniq(modelMixins);
 
   // Filter-in only mixins, that are used in models
   instructionsFromMixinSources = filterMixinInstructionsUsingWhitelist(
-    instructionsFromMixinSources, modelMixins
+    instructionsFromMixinSources, modelMixins,
   );
 
-  var mixins = _.assign(
+  const mixins = _.assign(
     instructionsFromMixins,
     instructionsFromMixinDirs,
-    instructionsFromMixinSources
+    instructionsFromMixinSources,
   );
 
   return _.values(mixins);
 }
 
 function findMixinDefinitions(appRootDir, sourceDirs, scriptExtensions) {
-  var files = [];
+  let files = [];
   sourceDirs.forEach(function(dir) {
-    var path = tryResolveAppPath(appRootDir, dir);
+    const path = tryResolveAppPath(appRootDir, dir);
     if (!path) {
       debug('Skipping unknown module source dir %j', dir);
       return;
@@ -99,15 +99,15 @@ function findMixinDefinitions(appRootDir, sourceDirs, scriptExtensions) {
 }
 
 function loadMixins(sourceFiles, normalization) {
-  var mixinInstructions = {};
+  const mixinInstructions = {};
   sourceFiles.forEach(function(filepath) {
-    var dir = path.dirname(filepath);
-    var ext = path.extname(filepath);
-    var name = path.basename(filepath, ext);
-    var metafile = path.join(dir, name + FILE_EXTENSION_JSON);
+    const dir = path.dirname(filepath);
+    const ext = path.extname(filepath);
+    let name = path.basename(filepath, ext);
+    const metafile = path.join(dir, name + FILE_EXTENSION_JSON);
 
     name = normalizeMixinName(name, normalization);
-    var meta = {};
+    const meta = {};
     meta.name = name;
     if (utils.fileExistsSync(metafile)) {
       // May overwrite name, not sourceFile
@@ -129,10 +129,10 @@ function fetchMixinNamesUsedInModelInstructions(modelInstructions) {
 }
 
 function filterMixinInstructionsUsingWhitelist(instructions, includeMixins) {
-  var instructionKeys = Object.keys(instructions);
+  const instructionKeys = Object.keys(instructions);
   includeMixins = _.intersection(instructionKeys, includeMixins);
 
-  var filteredInstructions = {};
+  const filteredInstructions = {};
   instructionKeys.forEach(function(mixinName) {
     if (includeMixins.indexOf(mixinName) !== -1) {
       filteredInstructions[mixinName] = instructions[mixinName];
@@ -168,7 +168,7 @@ function normalizeMixinName(str, normalization) {
         return normalization(str);
       }
 
-      var err = new Error(g.f('Invalid normalization format - "%s"',
+      const err = new Error(g.f('Invalid normalization format - "%s"',
         normalization));
       err.code = 'INVALID_NORMALIZATION_FORMAT';
       throw err;
@@ -176,18 +176,18 @@ function normalizeMixinName(str, normalization) {
 }
 
 Mixin.prototype.starting = function(context) {
-  var app = context.app;
-  var instructions = context.instructions.mixins;
+  const app = context.app;
+  const instructions = context.instructions.mixins;
 
-  var modelBuilder = (app.registry || app.loopback).modelBuilder;
-  var BaseClass = app.loopback.Model;
-  var mixins = instructions || [];
+  const modelBuilder = (app.registry || app.loopback).modelBuilder;
+  const BaseClass = app.loopback.Model;
+  const mixins = instructions || [];
 
   if (!modelBuilder.mixins || !mixins.length) return;
 
   mixins.forEach(function(obj) {
     debug('Requiring mixin %s', obj.sourceFile);
-    var mixin = require(obj.sourceFile);
+    const mixin = require(obj.sourceFile);
 
     if (typeof mixin === 'function' || mixin.prototype instanceof BaseClass) {
       debug('Defining mixin %s', obj.name);
diff --git a/lib/plugins/model.js b/lib/plugins/model.js
index f30b5a6..e8366e0 100644
--- a/lib/plugins/model.js
+++ b/lib/plugins/model.js
@@ -5,20 +5,20 @@
 
 'use strict';
 
-var assert = require('assert');
-var util = require('util');
-var PluginBase = require('../plugin-base');
-var path = require('path');
-var debug = require('debug')('loopback:boot:model');
-var _ = require('lodash');
-var toposort = require('toposort');
-var utils = require('../utils');
+const assert = require('assert');
+const util = require('util');
+const PluginBase = require('../plugin-base');
+const path = require('path');
+const debug = require('debug')('loopback:boot:model');
+const _ = require('lodash');
+const toposort = require('toposort');
+const utils = require('../utils');
 
-var tryReadDir = utils.tryReadDir;
-var assertIsValidConfig = utils.assertIsValidConfig;
-var tryResolveAppPath = utils.tryResolveAppPath;
-var fixFileExtension = utils.fixFileExtension;
-var g = require('../globalize');
+const tryReadDir = utils.tryReadDir;
+const assertIsValidConfig = utils.assertIsValidConfig;
+const tryResolveAppPath = utils.tryResolveAppPath;
+const fixFileExtension = utils.fixFileExtension;
+const g = require('../globalize');
 
 module.exports = function(options) {
   return new Model(options);
@@ -35,39 +35,42 @@ Model.prototype.getRootDir = function() {
 };
 
 Model.prototype.load = function(context) {
-  var config = PluginBase.prototype.load.apply(this, arguments);
+  const config = PluginBase.prototype.load.apply(this, arguments);
   assertIsValidModelConfig(config);
   return config;
 };
 
 Model.prototype.buildInstructions = function(context, rootDir, modelsConfig) {
-  var modelsMeta = modelsConfig._meta || {};
+  const modelsMeta = modelsConfig._meta || {};
   delete modelsConfig._meta;
   context.configurations.mixins._meta = modelsMeta;
 
-  var modelSources = this.options.modelSources || modelsMeta.sources ||
+  const modelSources = this.options.modelSources || modelsMeta.sources ||
     ['./models'];
-  var modelInstructions = buildAllModelInstructions(
+  const modelInstructions = buildAllModelInstructions(
     rootDir, modelsConfig, modelSources, this.options.modelDefinitions,
-    this.options.scriptExtensions
+    this.options.scriptExtensions,
   );
   return modelInstructions;
 };
 
 function buildAllModelInstructions(rootDir, modelsConfig, sources,
   modelDefinitions, scriptExtensions) {
-  var registry = verifyModelDefinitions(rootDir, modelDefinitions,
+  let registry = verifyModelDefinitions(rootDir, modelDefinitions,
     scriptExtensions);
   if (!registry) {
     registry = findModelDefinitions(rootDir, sources, scriptExtensions);
   }
 
-  var modelNamesToBuild = addAllBaseModels(registry, Object.keys(modelsConfig));
+  const modelNamesToBuild = addAllBaseModels(
+    registry,
+    Object.keys(modelsConfig),
+  );
 
-  var instructions = modelNamesToBuild
+  const instructions = modelNamesToBuild
     .map(function createModelInstructions(name) {
-      var config = modelsConfig[name];
-      var definition = registry[name] || {};
+      const config = modelsConfig[name];
+      const definition = registry[name] || {};
 
       debug('Using model "%s"\nConfiguration: %j\nDefinition %j',
         name, config, definition.definition);
@@ -84,20 +87,20 @@ function buildAllModelInstructions(rootDir, modelsConfig, sources,
 }
 
 function addAllBaseModels(registry, modelNames) {
-  var result = [];
-  var visited = {};
+  const result = [];
+  const visited = {};
 
   while (modelNames.length) {
-    var name = modelNames.shift();
+    const name = modelNames.shift();
 
     if (visited[name]) continue;
     visited[name] = true;
     result.push(name);
 
-    var definition = registry[name] && registry[name].definition;
+    const definition = registry[name] && registry[name].definition;
     if (!definition) continue;
 
-    var base = getBaseModelName(definition);
+    const base = getBaseModelName(definition);
 
     // ignore built-in models like User
     if (!registry[base]) continue;
@@ -118,14 +121,14 @@ function getBaseModelName(modelDefinition) {
 
 function sortByInheritance(instructions) {
   // create edges Base name -> Model name
-  var edges = instructions
+  const edges = instructions
     .map(function(inst) {
       return [getBaseModelName(inst.definition), inst.name];
     });
 
-  var sortedNames = toposort(edges);
+  const sortedNames = toposort(edges);
 
-  var instructionsByModelName = {};
+  const instructionsByModelName = {};
   instructions.forEach(function(inst) {
     instructionsByModelName[inst.name] = inst;
   });
@@ -146,14 +149,14 @@ function verifyModelDefinitions(rootDir, modelDefinitions, scriptExtensions) {
     return undefined;
   }
 
-  var registry = {};
+  const registry = {};
   modelDefinitions.forEach(function(definition, idx) {
     if (definition.sourceFile) {
-      var fullPath = path.resolve(rootDir, definition.sourceFile);
+      const fullPath = path.resolve(rootDir, definition.sourceFile);
       definition.sourceFile = fixFileExtension(
         fullPath,
         tryReadDir(path.dirname(fullPath)),
-        scriptExtensions
+        scriptExtensions,
       );
 
       if (!definition.sourceFile) {
@@ -168,7 +171,7 @@ function verifyModelDefinitions(rootDir, modelDefinitions, scriptExtensions) {
         path.relative(rootDir, definition.sourceFile) :
         '(no source file)');
 
-    var modelName = definition.definition.name;
+    const modelName = definition.definition.name;
     if (!modelName) {
       debug('Skipping model definition without Model name ' +
         '(from options.modelDefinitions @ index %s)',
@@ -182,26 +185,26 @@ function verifyModelDefinitions(rootDir, modelDefinitions, scriptExtensions) {
 }
 
 function findModelDefinitions(rootDir, sources, scriptExtensions) {
-  var registry = {};
+  const registry = {};
 
   sources.forEach(function(src) {
-    var srcDir = tryResolveAppPath(rootDir, src, {strict: false});
+    const srcDir = tryResolveAppPath(rootDir, src, {strict: false});
     if (!srcDir) {
       debug('Skipping unknown module source dir %j', src);
       return;
     }
 
-    var files = tryReadDir(srcDir);
+    const files = tryReadDir(srcDir);
 
     files
       .filter(function(f) {
         return f[0] !== '_' && path.extname(f) === '.json';
       })
       .forEach(function(f) {
-        var fullPath = path.resolve(srcDir, f);
-        var entry = loadModelDefinition(rootDir, fullPath, files,
+        const fullPath = path.resolve(srcDir, f);
+        const entry = loadModelDefinition(rootDir, fullPath, files,
           scriptExtensions);
-        var modelName = entry.definition.name;
+        const modelName = entry.definition.name;
         if (!modelName) {
           debug('Skipping model definition without Model name: %s',
             path.relative(srcDir, fullPath));
@@ -215,12 +218,12 @@ function findModelDefinitions(rootDir, sources, scriptExtensions) {
 }
 
 function loadModelDefinition(rootDir, jsonFile, allFiles, scriptExtensions) {
-  var definition = require(jsonFile);
-  var basename = path.basename(jsonFile, path.extname(jsonFile));
+  const definition = require(jsonFile);
+  const basename = path.basename(jsonFile, path.extname(jsonFile));
   definition.name = definition.name || _.upperFirst(_.camelCase(basename));
 
   // find a matching file with a supported extension like `.js` or `.coffee`
-  var sourceFile = fixFileExtension(jsonFile, allFiles, scriptExtensions);
+  const sourceFile = fixFileExtension(jsonFile, allFiles, scriptExtensions);
 
   if (sourceFile === undefined) {
     debug('Model source code not found: %s', sourceFile);
@@ -238,26 +241,26 @@ function loadModelDefinition(rootDir, jsonFile, allFiles, scriptExtensions) {
 
 function assertIsValidModelConfig(config) {
   assertIsValidConfig('model', config);
-  for (var name in config) {
-    var entry = config[name];
-    var options = entry.options || {};
-    var unsupported = entry.properties ||
+  for (const name in config) {
+    const entry = config[name];
+    const options = entry.options || {};
+    const unsupported = entry.properties ||
       entry.base || options.base ||
       entry.plural || options.plural;
 
     if (unsupported) {
       throw new Error(g.f(
         'The data in {{model-config.json}} ' +
-        'is in the unsupported {{1.x}} format.'
+        'is in the unsupported {{1.x}} format.',
       ));
     }
   }
 }
 
 // Regular expression to match built-in loopback models
-var LOOPBACK_MODEL_REGEXP = new RegExp(
+const LOOPBACK_MODEL_REGEXP = new RegExp(
   ['', 'node_modules', 'loopback', '[^\\/\\\\]+', 'models', '[^\\/\\\\]+\\.js$']
-    .join('\\' + path.sep)
+    .join('\\' + path.sep),
 );
 
 function isBuiltinLoopBackModel(app, data) {
@@ -265,19 +268,19 @@ function isBuiltinLoopBackModel(app, data) {
   if (!app.loopback[data.name]) return false;
 
   // 2. Built-in models have a script file `loopback/{facet}/models/{name}.js`
-  var srcFile = data.sourceFile;
+  const srcFile = data.sourceFile;
   return srcFile &&
     LOOPBACK_MODEL_REGEXP.test(srcFile);
 }
 
 Model.prototype.start = function(context) {
-  var app = context.app;
-  var instructions = context.instructions[this.name];
+  const app = context.app;
+  const instructions = context.instructions[this.name];
 
-  var registry = app.registry || app.loopback;
+  const registry = app.registry || app.loopback;
   instructions.forEach(function(data) {
-    var name = data.name;
-    var model;
+    const name = data.name;
+    let model;
 
     if (!data.definition) {
       model = registry.getModel(name);
@@ -294,7 +297,7 @@ Model.prototype.start = function(context) {
       model = registry.createModel(data.definition);
       if (data.sourceFile) {
         debug('Loading customization script %s', data.sourceFile);
-        var code = require(data.sourceFile);
+        const code = require(data.sourceFile);
         if (typeof code === 'function') {
           debug('Customizing model %s', name);
           code(model);
diff --git a/lib/plugins/swagger.js b/lib/plugins/swagger.js
index 761ea01..5dfcce9 100644
--- a/lib/plugins/swagger.js
+++ b/lib/plugins/swagger.js
@@ -5,8 +5,8 @@
 
 'use strict';
 
-var util = require('util');
-var PluginBase = require('../plugin-base');
+const util = require('util');
+const PluginBase = require('../plugin-base');
 
 module.exports = function(options) {
   return new Swagger(options);
@@ -19,13 +19,13 @@ function Swagger(options) {
 util.inherits(Swagger, PluginBase);
 
 Swagger.prototype.start = function(context) {
-  var app = context.app;
-  var appConfig = context.instructions.application;
+  const app = context.app;
+  const appConfig = context.instructions.application;
   // disable token requirement for swagger, if available
-  var swagger = app.remotes().exports.swagger;
+  const swagger = app.remotes().exports.swagger;
   if (!swagger) return;
 
-  var requireTokenForSwagger = appConfig.swagger &&
+  const requireTokenForSwagger = appConfig.swagger &&
     appConfig.swagger.requireToken;
   swagger.requireToken = requireTokenForSwagger || false;
 };
diff --git a/lib/utils.js b/lib/utils.js
index 7c6573e..ddbc8ac 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -5,13 +5,13 @@
 
 'use strict';
 
-var debug = require('debug')('loopback:boot');
-var path = require('path');
-var Module = require('module');
-var fs = require('fs');
-var assert = require('assert');
-var _ = require('lodash');
-var g = require('./globalize');
+const debug = require('debug')('loopback:boot');
+const path = require('path');
+const Module = require('module');
+const fs = require('fs');
+const assert = require('assert');
+const _ = require('lodash');
+const g = require('./globalize');
 
 exports.arrayToObject = arrayToObject;
 exports.tryReadDir = tryReadDir;
@@ -26,7 +26,7 @@ exports.tryResolveAppPath = tryResolveAppPath;
 exports.forEachKeyedObject = forEachKeyedObject;
 exports.mergePhaseNameLists = mergePhaseNameLists;
 
-var FILE_EXTENSION_JSON = exports.FILE_EXTENSION_JSON = '.json';
+const FILE_EXTENSION_JSON = exports.FILE_EXTENSION_JSON = '.json';
 /**
  * Find all javascript files (except for those prefixed with _)
  * and all directories.
@@ -37,7 +37,7 @@ var FILE_EXTENSION_JSON = exports.FILE_EXTENSION_JSON = '.json';
 function findScripts(dir, scriptExtensions) {
   assert(dir, 'cannot require directory contents without directory name');
 
-  var files = tryReadDir(dir);
+  const files = tryReadDir(dir);
   scriptExtensions = scriptExtensions || require.extensions;
 
   // sort files in lowercase alpha for linux
@@ -54,15 +54,15 @@ function findScripts(dir, scriptExtensions) {
     }
   });
 
-  var results = [];
+  const results = [];
   files.forEach(function(filename) {
     // ignore index.js and files prefixed with underscore
     if (filename === 'index.js' || filename[0] === '_') {
       return;
     }
 
-    var filepath = path.resolve(path.join(dir, filename));
-    var stats = fs.statSync(filepath);
+    const filepath = path.resolve(path.join(dir, filename));
+    const stats = fs.statSync(filepath);
 
     // only require files supported by specified extensions
     if (stats.isFile()) {
@@ -87,9 +87,13 @@ function tryReadDir() {
 }
 
 function resolveRelativePaths(relativePaths, appRootDir) {
-  var resolveOpts = {strict: false};
+  const resolveOpts = {strict: false};
   relativePaths.forEach(function(relativePath, k) {
-    var resolvedPath = tryResolveAppPath(appRootDir, relativePath, resolveOpts);
+    const resolvedPath = tryResolveAppPath(
+      appRootDir,
+      relativePath,
+      resolveOpts,
+    );
     if (resolvedPath !== undefined) {
       relativePaths[k] = resolvedPath;
     } else {
@@ -121,28 +125,28 @@ function arrayToObject(array) {
 function isPreferredExtension(filename, includeExtensions) {
   assert(!!includeExtensions, '"includeExtensions" argument is required');
 
-  var ext = path.extname(filename);
+  const ext = path.extname(filename);
   return (ext in includeExtensions) && !(ext in getExcludedExtensions());
 }
 
 function fixFileExtension(filepath, files, scriptExtensions) {
-  var results = [];
-  var otherFile;
+  const results = [];
+  let otherFile;
 
   /* Prefer coffee scripts over json */
   if (scriptExtensions && isPreferredExtension(filepath, scriptExtensions)) {
     return filepath;
   }
 
-  var basename = path.basename(filepath, FILE_EXTENSION_JSON);
-  var sourceDir = path.dirname(filepath);
+  const basename = path.basename(filepath, FILE_EXTENSION_JSON);
+  const sourceDir = path.dirname(filepath);
 
   files.forEach(function(f) {
     otherFile = path.resolve(sourceDir, f);
 
-    var stats = fs.statSync(otherFile);
+    const stats = fs.statSync(otherFile);
     if (stats.isFile()) {
-      var otherFileExtension = path.extname(f);
+      const otherFileExtension = path.extname(f);
 
       if (!(otherFileExtension in getExcludedExtensions()) &&
         path.basename(f, otherFileExtension) == basename) {
@@ -156,9 +160,9 @@ function fixFileExtension(filepath, files, scriptExtensions) {
 }
 
 function resolveAppPath(rootDir, relativePath, resolveOptions) {
-  var resolvedPath = tryResolveAppPath(rootDir, relativePath, resolveOptions);
+  const resolvedPath = tryResolveAppPath(rootDir, relativePath, resolveOptions);
   if (resolvedPath === undefined && !resolveOptions.optional) {
-    var err = new Error(g.f('Cannot resolve path "%s"', relativePath));
+    const err = new Error(g.f('Cannot resolve path "%s"', relativePath));
     err.code = 'PATH_NOT_FOUND';
     throw err;
   }
@@ -166,19 +170,19 @@ function resolveAppPath(rootDir, relativePath, resolveOptions) {
 }
 
 function resolveAppScriptPath(rootDir, relativePath, resolveOptions) {
-  var resolvedPath = resolveAppPath(rootDir, relativePath, resolveOptions);
+  const resolvedPath = resolveAppPath(rootDir, relativePath, resolveOptions);
   if (!resolvedPath) {
     return false;
   }
-  var sourceDir = path.dirname(resolvedPath);
-  var files = tryReadDir(sourceDir);
-  var fixedFile = fixFileExtension(resolvedPath, files);
+  const sourceDir = path.dirname(resolvedPath);
+  const files = tryReadDir(sourceDir);
+  const fixedFile = fixFileExtension(resolvedPath, files);
   return (fixedFile === undefined ? resolvedPath : fixedFile);
 }
 
 function tryResolveAppPath(rootDir, relativePath, resolveOptions) {
-  var fullPath;
-  var start = relativePath.substring(0, 2);
+  let fullPath;
+  const start = relativePath.substring(0, 2);
 
   /* In order to retain backward compatibility, we need to support
    * two ways how to treat values that are not relative nor absolute
@@ -189,7 +193,7 @@ function tryResolveAppPath(rootDir, relativePath, resolveOptions) {
    */
   resolveOptions = resolveOptions || {strict: true};
 
-  var isModuleRelative = false;
+  let isModuleRelative = false;
   if (relativePath[0] === '/') {
     fullPath = relativePath;
   } else if (start === './' || start === '..') {
@@ -222,17 +226,17 @@ function tryResolveAppPath(rootDir, relativePath, resolveOptions) {
   //   [ env.NODE_PATH values, $HOME/.node_modules, etc. ]
   // Module._nodeModulePaths(rootDir) returns a list of paths like
   //   [ rootDir/node_modules, rootDir/../node_modules, etc. ]
-  var modulePaths = Module.globalPaths
+  const modulePaths = Module.globalPaths
     .concat(Module._nodeModulePaths(rootDir));
 
   fullPath = modulePaths
     .map(function(candidateDir) {
-      var absPath = path.join(candidateDir, relativePath);
+      const absPath = path.join(candidateDir, relativePath);
       try {
         // NOTE(bajtos) We need to create a proper String object here,
         // otherwise we can't attach additional properties to it
         /* jshint -W053 */
-        var filePath = new String(require.resolve(absPath));
+        const filePath = new String(require.resolve(absPath));
         filePath.unresolvedPath = absPath;
         return filePath;
       } catch (err) {
@@ -310,8 +314,8 @@ function forEachKeyedObject(obj, fn) {
 function mergePhaseNameLists(currentNames, namesToMerge) {
   if (!namesToMerge.length) return currentNames.slice();
 
-  var targetArray = currentNames.slice();
-  var targetIx = targetArray.indexOf(namesToMerge[0]);
+  const targetArray = currentNames.slice();
+  let targetIx = targetArray.indexOf(namesToMerge[0]);
 
   if (targetIx === -1) {
     // the first new item does not match any existing one
@@ -321,21 +325,21 @@ function mergePhaseNameLists(currentNames, namesToMerge) {
   }
 
   // merge (zip) two arrays
-  for (var sourceIx = 1; sourceIx < namesToMerge.length; sourceIx++) {
-    var valueToAdd = namesToMerge[sourceIx];
-    var previousValue = namesToMerge[sourceIx - 1];
-    var existingIx = targetArray.indexOf(valueToAdd, targetIx);
+  for (let sourceIx = 1; sourceIx < namesToMerge.length; sourceIx++) {
+    const valueToAdd = namesToMerge[sourceIx];
+    const previousValue = namesToMerge[sourceIx - 1];
+    const existingIx = targetArray.indexOf(valueToAdd, targetIx);
 
     if (existingIx === -1) {
       // A new phase - try to add it after the last one,
       // unless it was already registered
       if (targetArray.indexOf(valueToAdd) !== -1) {
-        var errMsg = g.f('Ordering conflict: cannot add "%s' +
+        const errMsg = g.f('Ordering conflict: cannot add "%s' +
           '" after "%s", because the opposite order was ' +
           ' already specified', valueToAdd, previousValue);
         throw new Error(errMsg);
       }
-      var previousIx = targetArray.indexOf(previousValue);
+      const previousIx = targetArray.indexOf(previousValue);
       targetArray.splice(previousIx + 1, 0, valueToAdd);
     } else {
       // An existing phase - move the pointer
diff --git a/package.json b/package.json
index 1b78c6f..a9b60c8 100644
--- a/package.json
+++ b/package.json
@@ -40,8 +40,8 @@
     "coffeeify": "^3.0.1",
     "coffeescript": "^2.3.1",
     "dirty-chai": "^2.0.1",
-    "eslint": "^5.2.0",
-    "eslint-config-loopback": "^11.0.0",
+    "eslint": "^6.6.0",
+    "eslint-config-loopback": "^13.1.0",
     "fs-extra": "^7.0.1",
     "loopback": "^3.0.0",
     "mocha": "^5.2.0",
diff --git a/test/acceptance.test.js b/test/acceptance.test.js
index 6bb7dcd..f39622f 100644
--- a/test/acceptance.test.js
+++ b/test/acceptance.test.js
@@ -5,18 +5,18 @@
 
 'use strict';
 
-var path = require('path');
-var loopback = require('loopback');
+const path = require('path');
+const loopback = require('loopback');
 
-var chai = require('chai');
-var dirtyChai = require('dirty-chai');
-var expect = chai.expect;
+const chai = require('chai');
+const dirtyChai = require('dirty-chai');
+const expect = chai.expect;
 chai.use(dirtyChai);
 
 const bootLoopBackApp = require('..');
 
 describe('bootLoopBackApp', function() {
-  var app;
+  let app;
   beforeEach(function() {
     app = loopback();
   });
diff --git a/test/bootstrapper.test.js b/test/bootstrapper.test.js
index d32ac72..d76d6f2 100644
--- a/test/bootstrapper.test.js
+++ b/test/bootstrapper.test.js
@@ -5,39 +5,39 @@
 
 'use strict';
 
-var path = require('path');
-var loopback = require('loopback');
+const path = require('path');
+const loopback = require('loopback');
 
-var chai = require('chai');
-var dirtyChai = require('dirty-chai');
-var expect = chai.expect;
+const chai = require('chai');
+const dirtyChai = require('dirty-chai');
+const expect = chai.expect;
 chai.use(dirtyChai);
 
-var Bootstrapper = require('../lib/bootstrapper');
+const Bootstrapper = require('../lib/bootstrapper');
 
 describe('Bootstrapper', function() {
-  var app;
+  let app;
   beforeEach(function() {
     app = loopback();
     process.bootFlags = [];
   });
 
   it('should honor options.phases', function(done) {
-    var options = {
+    const options = {
       app: app,
       appRootDir: path.join(__dirname, './fixtures/simple-app'),
       phases: ['load'],
     };
 
-    var bootstrapper = new Bootstrapper(options);
+    const bootstrapper = new Bootstrapper(options);
 
-    var context = {
+    const context = {
       app: app,
     };
 
     bootstrapper.run(context, function(err) {
       if (err) return done(err);
-      var configs = context.configurations;
+      const configs = context.configurations;
       expect(configs.application, 'application').to.be.an('object');
       expect(configs.bootScripts, 'bootScripts').to.be.an('array');
       expect(configs.middleware, 'middleware').to.be.an('object');
@@ -50,22 +50,22 @@ describe('Bootstrapper', function() {
   });
 
   it('should honor options.plugins', function(done) {
-    var options = {
+    const options = {
       app: app,
       appRootDir: path.join(__dirname, './fixtures/simple-app'),
       plugins: ['application', 'boot-script'],
     };
 
-    var bootstrapper = new Bootstrapper(options);
+    const bootstrapper = new Bootstrapper(options);
 
-    var context = {
+    const context = {
       app: app,
     };
 
     bootstrapper.run(context, function(err) {
       if (err) return done(err);
-      var configs = context.configurations;
-      var instructions = context.instructions;
+      const configs = context.configurations;
+      const instructions = context.instructions;
       expect(configs.application, 'application').to.be.an('object');
       expect(configs.middleware, 'middleware').to.be.undefined();
       expect(configs.models, 'models').to.be.undefined();
@@ -94,15 +94,15 @@ describe('Bootstrapper', function() {
 
   it('searches boot file extensions specified in options.scriptExtensions',
     function(done) {
-      var options = {
+      const options = {
         app: app,
         appRootDir: path.join(__dirname, './fixtures/simple-app'),
         scriptExtensions: ['.customjs', '.customjs2'],
       };
 
-      var bootstrapper = new Bootstrapper(options);
+      const bootstrapper = new Bootstrapper(options);
 
-      var context = {
+      const context = {
         app: app,
       };
 
diff --git a/test/browser.multiapp.test.js b/test/browser.multiapp.test.js
index 3cd18a5..e8608ff 100644
--- a/test/browser.multiapp.test.js
+++ b/test/browser.multiapp.test.js
@@ -5,18 +5,18 @@
 
 'use strict';
 
-var boot = require('../');
-var async = require('async');
-var exportBrowserifyToFile = require('./helpers/browserify').exportToSandbox;
-var packageFilter = require('./helpers/browserify').packageFilter;
-var fs = require('fs');
-var path = require('path');
-var expect = require('chai').expect;
-var browserify = require('browserify');
-var sandbox = require('./helpers/sandbox');
-var vm = require('vm');
-var createBrowserLikeContext = require('./helpers/browser').createContext;
-var printContextLogs = require('./helpers/browser').printContextLogs;
+const boot = require('../');
+const async = require('async');
+const exportBrowserifyToFile = require('./helpers/browserify').exportToSandbox;
+const packageFilter = require('./helpers/browserify').packageFilter;
+const fs = require('fs');
+const path = require('path');
+const expect = require('chai').expect;
+const browserify = require('browserify');
+const sandbox = require('./helpers/sandbox');
+const vm = require('vm');
+const createBrowserLikeContext = require('./helpers/browser').createContext;
+const printContextLogs = require('./helpers/browser').printContextLogs;
 
 describe('browser support for multiple apps', function() {
   this.timeout(60000); // 60s to give browserify enough time to finish
@@ -24,10 +24,10 @@ describe('browser support for multiple apps', function() {
   beforeEach(sandbox.reset);
 
   it('has API for bundling and booting multiple apps', function(done) {
-    var app1Dir = path.resolve(__dirname, './fixtures/browser-app');
-    var app2Dir = path.resolve(__dirname, './fixtures/browser-app-2');
+    const app1Dir = path.resolve(__dirname, './fixtures/browser-app');
+    const app2Dir = path.resolve(__dirname, './fixtures/browser-app-2');
 
-    var apps = [
+    const apps = [
       {
         appDir: app1Dir,
         appFile: './app.js',
@@ -44,9 +44,9 @@ describe('browser support for multiple apps', function() {
     browserifyTestApps(apps, function(err, bundlePath) {
       if (err) return done(err);
 
-      var bundledApps = executeBundledApps(bundlePath, apps, function(err) {
-        var app1 = bundledApps.defaultApp;
-        var app2 = bundledApps.browserApp2;
+      const bundledApps = executeBundledApps(bundlePath, apps, function(err) {
+        const app1 = bundledApps.defaultApp;
+        const app2 = bundledApps.browserApp2;
 
         expect(app1.settings).to.have.property('custom-key', 'custom-value');
         expect(Object.keys(app1.models)).to.include('Customer');
@@ -64,23 +64,23 @@ describe('browser support for multiple apps', function() {
 });
 
 function browserifyTestApps(apps, next) {
-  var b = browserify({
+  const b = browserify({
     debug: true,
     basedir: path.resolve(__dirname, './fixtures'),
     packageFilter,
   });
 
-  var bundles = [];
-  for (var i in apps) {
-    var appDir = apps[i].appDir;
-    var appFile = apps[i].appFile;
-    var moduleName = apps[i].moduleName;
-    var appId = apps[i].appId;
+  const bundles = [];
+  for (const i in apps) {
+    const appDir = apps[i].appDir;
+    let appFile = apps[i].appFile;
+    const moduleName = apps[i].moduleName;
+    const appId = apps[i].appId;
 
     appFile = path.join(appDir, appFile);
     b.require(appFile, {expose: moduleName});
 
-    var opts = appDir;
+    let opts = appDir;
     if (appId) {
       opts = {
         appId: appId,
@@ -97,21 +97,21 @@ function browserifyTestApps(apps, next) {
 }
 
 function executeBundledApps(bundlePath, apps, done) {
-  var code = fs.readFileSync(bundlePath);
-  var context = createBrowserLikeContext();
+  const code = fs.readFileSync(bundlePath);
+  const context = createBrowserLikeContext();
   vm.runInContext(code, context, bundlePath);
 
-  var ids = [];
-  var script = 'var apps = {};\n';
-  for (var i in apps) {
-    var moduleName = apps[i].moduleName;
-    var id = apps[i].appId || 'defaultApp';
+  const ids = [];
+  let script = 'var apps = {};\n';
+  for (const i in apps) {
+    const moduleName = apps[i].moduleName;
+    const id = apps[i].appId || 'defaultApp';
     ids.push(id);
     script += 'apps.' + id + ' = require("' + moduleName + '");\n';
   }
   script += 'apps;\n';
 
-  var appsInContext = vm.runInContext(script, context);
+  const appsInContext = vm.runInContext(script, context);
   async.each(ids, function(id, done) {
     appsInContext[id].once('booted', function() {
       done();
diff --git a/test/browser.test.js b/test/browser.test.js
index e59ba08..f0de610 100644
--- a/test/browser.test.js
+++ b/test/browser.test.js
@@ -5,21 +5,21 @@
 
 'use strict';
 
-var boot = require('../');
-var exportBrowserifyToFile = require('./helpers/browserify').exportToSandbox;
-var packageFilter = require('./helpers/browserify').packageFilter;
-var fs = require('fs');
-var path = require('path');
-var expect = require('chai').expect;
-var browserify = require('browserify');
-var sandbox = require('./helpers/sandbox');
-var vm = require('vm');
-var createBrowserLikeContext = require('./helpers/browser').createContext;
-var printContextLogs = require('./helpers/browser').printContextLogs;
+const boot = require('../');
+const exportBrowserifyToFile = require('./helpers/browserify').exportToSandbox;
+const packageFilter = require('./helpers/browserify').packageFilter;
+const fs = require('fs');
+const path = require('path');
+const expect = require('chai').expect;
+const browserify = require('browserify');
+const sandbox = require('./helpers/sandbox');
+const vm = require('vm');
+const createBrowserLikeContext = require('./helpers/browser').createContext;
+const printContextLogs = require('./helpers/browser').printContextLogs;
 
-var compileStrategies = {
+const compileStrategies = {
   default: function(appDir) {
-    var b = browserify({
+    const b = browserify({
       basedir: appDir,
       debug: true,
       packageFilter,
@@ -29,7 +29,7 @@ var compileStrategies = {
   },
 
   coffee: function(appDir) {
-    var b = browserify({
+    const b = browserify({
       basedir: appDir,
       extensions: ['.coffee'],
       debug: true,
@@ -48,19 +48,19 @@ describe('browser support', function() {
   beforeEach(sandbox.reset);
 
   it('has API for bundling and executing boot instructions', function(done) {
-    var appDir = path.resolve(__dirname, './fixtures/browser-app');
+    const appDir = path.resolve(__dirname, './fixtures/browser-app');
 
     browserifyTestApp(appDir, function(err, bundlePath) {
       if (err) return done(err);
 
-      var app = executeBundledApp(bundlePath, function(err) {
+      const app = executeBundledApp(bundlePath, function(err) {
         if (err) return done(err);
         // configured in fixtures/browser-app/boot/configure.js
         expect(app.settings).to.have.property('custom-key', 'custom-value');
         expect(Object.keys(app.models)).to.include('Customer');
         expect(app.models.Customer.settings).to.have.property(
           '_customized',
-          'Customer'
+          'Customer',
         );
 
         // configured in fixtures/browser-app/component-config.json
@@ -72,17 +72,17 @@ describe('browser support', function() {
   });
 
   it('loads mixins', function(done) {
-    var appDir = path.resolve(__dirname, './fixtures/browser-app');
-    var options = {
+    const appDir = path.resolve(__dirname, './fixtures/browser-app');
+    const options = {
       appRootDir: appDir,
     };
 
     browserifyTestApp(options, function(err, bundlePath) {
       if (err) return done(err);
 
-      var app = executeBundledApp(bundlePath, function(err) {
-        var modelBuilder = app.registry.modelBuilder;
-        var registry = modelBuilder.mixins.mixins;
+      const app = executeBundledApp(bundlePath, function(err) {
+        const modelBuilder = app.registry.modelBuilder;
+        const registry = modelBuilder.mixins.mixins;
         expect(Object.keys(registry)).to.eql(['TimeStamps']);
         expect(app.models.Customer.timeStampsMixin).to.eql(true);
 
@@ -95,18 +95,18 @@ describe('browser support', function() {
     // add coffee-script to require.extensions
     require('coffeescript/register');
 
-    var appDir = path.resolve(__dirname, './fixtures/coffee-app');
+    const appDir = path.resolve(__dirname, './fixtures/coffee-app');
 
     browserifyTestApp(appDir, 'coffee', function(err, bundlePath) {
       if (err) return done(err);
 
-      var app = executeBundledApp(bundlePath, function(err) {
+      const app = executeBundledApp(bundlePath, function(err) {
         // configured in fixtures/browser-app/boot/configure.coffee
         expect(app.settings).to.have.property('custom-key', 'custom-value');
         expect(Object.keys(app.models)).to.include('Customer');
         expect(app.models.Customer.settings).to.have.property(
           '_customized',
-          'Customer'
+          'Customer',
         );
         done();
       });
@@ -122,8 +122,8 @@ function browserifyTestApp(options, strategy, next) {
   }
   if (!strategy) strategy = 'default';
 
-  var appDir = typeof options === 'object' ? options.appRootDir : options;
-  var b = compileStrategies[strategy](appDir);
+  const appDir = typeof options === 'object' ? options.appRootDir : options;
+  const b = compileStrategies[strategy](appDir);
 
   boot.compileToBrowserify(options, b, function(err) {
     exportBrowserifyToFile(b, 'browser-app-bundle.js', next);
@@ -131,10 +131,10 @@ function browserifyTestApp(options, strategy, next) {
 }
 
 function executeBundledApp(bundlePath, done) {
-  var code = fs.readFileSync(bundlePath);
-  var context = createBrowserLikeContext();
+  const code = fs.readFileSync(bundlePath);
+  const context = createBrowserLikeContext();
   vm.runInContext(code, context, bundlePath);
-  var app = vm.runInContext('require("browser-app")', context);
+  const app = vm.runInContext('require("browser-app")', context);
   app.once('booted', function(err) {
     printContextLogs(context);
     done(err, app);
diff --git a/test/compiler.test.js b/test/compiler.test.js
index 5af498a..bfd90d7 100644
--- a/test/compiler.test.js
+++ b/test/compiler.test.js
@@ -5,17 +5,17 @@
 
 'use strict';
 
-var boot = require('../');
-var fs = require('fs-extra');
-var path = require('path');
-var expect = require('chai').expect;
-var sandbox = require('./helpers/sandbox');
-var appdir = require('./helpers/appdir');
+const boot = require('../');
+const fs = require('fs-extra');
+const path = require('path');
+const expect = require('chai').expect;
+const sandbox = require('./helpers/sandbox');
+const appdir = require('./helpers/appdir');
 
 // add coffee-script to require.extensions
 require('coffeescript/register');
 
-var SIMPLE_APP = path.join(__dirname, 'fixtures', 'simple-app');
+const SIMPLE_APP = path.join(__dirname, 'fixtures', 'simple-app');
 
 describe('compiler', function() {
   beforeEach(sandbox.reset);
@@ -48,7 +48,7 @@ describe('compiler', function() {
   }
 
   describe('from options', function() {
-    var options, instructions, appConfig;
+    let options, instructions, appConfig;
 
     beforeEach(function(done) {
       options = {
@@ -115,12 +115,12 @@ describe('compiler', function() {
     });
 
     describe('with custom model definitions', function(done) {
-      var dataSources = {
+      const dataSources = {
         'the-db': {connector: 'memory'},
       };
 
       it('loads model without definition', function(done) {
-        var instruction = boot.compile(
+        const instruction = boot.compile(
           {
             appRootDir: appdir.PATH,
             models: {
@@ -133,21 +133,21 @@ describe('compiler', function() {
           },
           function(err, context) {
             if (err) return done(err);
-            var instructions = context.instructions;
+            const instructions = context.instructions;
             expect(instructions.models[0].name).to.equal(
-              'model-without-definition'
+              'model-without-definition',
             );
             expect(instructions.models[0].definition).to.equal(undefined);
             expect(instructions.models[0].sourceFile).to.equal(undefined);
             done();
-          }
+          },
         );
       });
 
       it('loads coffeescript models', function(done) {
-        var modelScript = appdir.writeFileSync(
+        const modelScript = appdir.writeFileSync(
           'custom-models/coffee-model-with-definition.coffee',
-          ''
+          '',
         );
         boot.compile(
           {
@@ -169,23 +169,23 @@ describe('compiler', function() {
           },
           function(err, context) {
             if (err) return done(err);
-            var instructions = context.instructions;
+            const instructions = context.instructions;
             expect(instructions.models[0].name).to.equal(
-              'coffee-model-with-definition'
+              'coffee-model-with-definition',
             );
             expect(instructions.models[0].definition).to.eql({
               name: 'coffee-model-with-definition',
             });
             expect(instructions.models[0].sourceFile).to.equal(modelScript);
             done();
-          }
+          },
         );
       });
 
       it('handles sourceFile path without extension (.js)', function(done) {
-        var modelScript = appdir.writeFileSync(
+        const modelScript = appdir.writeFileSync(
           'custom-models/model-without-ext.coffee',
-          ''
+          '',
         );
         boot.compile(
           {
@@ -207,18 +207,18 @@ describe('compiler', function() {
           },
           function(err, context) {
             if (err) return done(err);
-            var instructions = context.instructions;
+            const instructions = context.instructions;
             expect(instructions.models[0].name).to.equal('model-without-ext');
             expect(instructions.models[0].sourceFile).to.equal(modelScript);
             done();
-          }
+          },
         );
       });
 
       it('handles sourceFile path without extension (.coffee)', function(done) {
-        var modelScript = appdir.writeFileSync(
+        const modelScript = appdir.writeFileSync(
           'custom-models/model-without-ext.coffee',
-          ''
+          '',
         );
         boot.compile(
           {
@@ -240,18 +240,18 @@ describe('compiler', function() {
           },
           function(err, context) {
             if (err) return done(err);
-            var instructions = context.instructions;
+            const instructions = context.instructions;
             expect(instructions.models[0].name).to.equal('model-without-ext');
             expect(instructions.models[0].sourceFile).to.equal(modelScript);
             done();
-          }
+          },
         );
       });
 
       it('sets source file path if the file exist', function(done) {
-        var modelScript = appdir.writeFileSync(
+        const modelScript = appdir.writeFileSync(
           'custom-models/model-with-definition.js',
-          ''
+          '',
         );
         boot.compile(
           {
@@ -273,14 +273,14 @@ describe('compiler', function() {
           },
           function(err, context) {
             if (err) return done(err);
-            var instructions = context.instructions;
+            const instructions = context.instructions;
             expect(instructions.models[0].name).to.equal(
-              'model-with-definition'
+              'model-with-definition',
             );
             expect(instructions.models[0].definition).not.to.equal(undefined);
             expect(instructions.models[0].sourceFile).to.equal(modelScript);
             done();
-          }
+          },
         );
       });
 
@@ -301,7 +301,7 @@ describe('compiler', function() {
                   },
                   sourceFile: appdir.resolve(
                     'custom-models',
-                    'file-does-not-exist.js'
+                    'file-does-not-exist.js',
                   ),
                 },
               ],
@@ -309,14 +309,14 @@ describe('compiler', function() {
             },
             function(err, context) {
               if (err) return done(err);
-              var instructions = context.instructions;
+              const instructions = context.instructions;
               expect(instructions.models[0].name).to.equal(
-                'model-with-definition-with-falsey-source-file'
+                'model-with-definition-with-falsey-source-file',
               );
               expect(instructions.models[0].definition).not.to.equal(undefined);
               expect(instructions.models[0].sourceFile).to.equal(undefined);
               done();
-            }
+            },
           );
         });
 
@@ -342,14 +342,14 @@ describe('compiler', function() {
             },
             function(err, context) {
               if (err) return done(err);
-              var instructions = context.instructions;
+              const instructions = context.instructions;
               expect(instructions.models[0].name).to.equal(
-                'model-with-definition-without-source-file-property'
+                'model-with-definition-without-source-file-property',
               );
               expect(instructions.models[0].definition).not.to.equal(undefined);
               expect(instructions.models[0].sourceFile).to.equal(undefined);
               done();
-            }
+            },
           );
         });
 
@@ -378,12 +378,12 @@ describe('compiler', function() {
           },
           function(err, context) {
             if (err) return done(err);
-            var instructions = context.instructions;
+            const instructions = context.instructions;
             expect(instructions.models.map(getNameProperty)).to.eql([
               'some-model',
             ]);
             done();
-          }
+          },
         );
       });
     });
@@ -393,7 +393,7 @@ describe('compiler', function() {
     it('loads config files', function(done) {
       boot.compile(SIMPLE_APP, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
         expect(instructions.models).to.have.length(1);
         expect(instructions.models[0]).to.eql({
@@ -414,21 +414,21 @@ describe('compiler', function() {
         db: {local: 'applied'},
       });
 
-      var env = process.env.NODE_ENV || 'development';
+      const env = process.env.NODE_ENV || 'development';
       appdir.writeConfigFileSync('datasources.' + env + '.json', {
         db: {env: 'applied'},
       });
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
-        var db = instructions.dataSources.db;
+        const db = instructions.dataSources.db;
         expect(db).to.have.property('local', 'applied');
         expect(db).to.have.property('env', 'applied');
 
-        var expectedLoadOrder = ['local', 'env'];
-        var actualLoadOrder = Object.keys(db).filter(function(k) {
+        const expectedLoadOrder = ['local', 'env'];
+        const actualLoadOrder = Object.keys(db).filter(function(k) {
           return expectedLoadOrder.indexOf(k) !== -1;
         });
 
@@ -441,21 +441,21 @@ describe('compiler', function() {
       appdir.createConfigFilesSync();
       appdir.writeFileSync(
         'datasources.local.js',
-        'module.exports = { db: { fromJs: true } };'
+        'module.exports = { db: { fromJs: true } };',
       );
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
-        var db = instructions.dataSources.db;
+        const db = instructions.dataSources.db;
         expect(db).to.have.property('fromJs', true);
         done();
       });
     });
 
     it('merges new Object values', function(done) {
-      var objectValue = {key: 'value'};
+      const objectValue = {key: 'value'};
       appdir.createConfigFilesSync();
       appdir.writeConfigFileSync('datasources.local.json', {
         db: {nested: objectValue},
@@ -463,9 +463,9 @@ describe('compiler', function() {
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
-        var db = instructions.dataSources.db;
+        const db = instructions.dataSources.db;
         expect(db).to.have.property('nested');
         expect(db.nested).to.eql(objectValue);
         done();
@@ -481,7 +481,7 @@ describe('compiler', function() {
               host: 'localhost',
             },
           },
-        }
+        },
       );
 
       appdir.writeConfigFileSync('datasources.local.json', {
@@ -494,8 +494,8 @@ describe('compiler', function() {
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
-        var email = instructions.dataSources.email;
+        const instructions = context.instructions;
+        const email = instructions.dataSources.email;
         expect(email.transport.host).to.equal('mail.example.com');
         done();
       });
@@ -515,7 +515,7 @@ describe('compiler', function() {
               },
             ],
           },
-        }
+        },
       );
       appdir.writeConfigFileSync('datasources.local.json', {
         rest: {
@@ -531,9 +531,9 @@ describe('compiler', function() {
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
-        var rest = instructions.dataSources.rest;
+        const rest = instructions.dataSources.rest;
         expect(rest.operations[0].template).to.eql({
           method: 'POST', // the value from datasources.json
           url: 'http://api.example.com', // overriden in datasources.local.json
@@ -543,7 +543,7 @@ describe('compiler', function() {
     });
 
     it('merges Array properties', function(done) {
-      var arrayValue = ['value'];
+      const arrayValue = ['value'];
       appdir.createConfigFilesSync();
       appdir.writeConfigFileSync('datasources.local.json', {
         db: {nested: arrayValue},
@@ -551,9 +551,9 @@ describe('compiler', function() {
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
-        var db = instructions.dataSources.db;
+        const db = instructions.dataSources.db;
         expect(db).to.have.property('nested');
         expect(db.nested).to.eql(arrayValue);
         done();
@@ -570,28 +570,28 @@ describe('compiler', function() {
       });
 
       // Here we load main config and merge it with DEV overrides
-      var bootOptions = {
+      const bootOptions = {
         appRootDir: appdir.PATH,
         env: 'development',
         phases: ['load'],
       };
-      var productionBootOptions = {
+      const productionBootOptions = {
         appRootDir: appdir.PATH,
         env: 'production',
         phases: ['load'],
       };
       boot.compile(bootOptions, function(err, context) {
-        var config = context.configurations.middleware;
+        const config = context.configurations.middleware;
         expect(
           config['strong-error-handler'].params.debug,
-          'debug in development'
+          'debug in development',
         ).to.equal(true);
 
         boot.compile(productionBootOptions, function(err, context2) {
-          var config = context2.configurations.middleware;
+          const config = context2.configurations.middleware;
           expect(
             config['strong-error-handler'].params.debug,
-            'debug in production'
+            'debug in production',
           ).to.equal(false);
           done();
         });
@@ -606,7 +606,7 @@ describe('compiler', function() {
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
         expect(instructions.models).to.have.length(1);
         expect(instructions.models[0]).to.have.property('name', 'foo');
@@ -624,7 +624,7 @@ describe('compiler', function() {
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
         expect(instructions.models).to.have.length(1);
         expect(instructions.models[0]).to.have.property('name', 'foo');
@@ -640,12 +640,12 @@ describe('compiler', function() {
       appdir.createConfigFilesSync();
       appdir.writeFileSync(
         'model-config.local.js',
-        "module.exports = { foo: { dataSource: 'db' } };"
+        "module.exports = { foo: { dataSource: 'db' } };",
       );
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
         expect(instructions.models).to.have.length(1);
         expect(instructions.models[0]).to.have.property('name', 'foo');
@@ -672,7 +672,7 @@ describe('compiler', function() {
 
       expectCompileToThrow(
         /array values of different length.*nest\.array/,
-        done
+        done,
       );
     });
 
@@ -707,7 +707,7 @@ describe('compiler', function() {
 
       expectCompileToThrow(
         /array values of different length.*toplevel\[0\]\.nested/,
-        done
+        done,
       );
     });
 
@@ -738,21 +738,21 @@ describe('compiler', function() {
 
       appdir.writeConfigFileSync('config.local.json', {cfgLocal: 'applied'});
 
-      var env = process.env.NODE_ENV || 'development';
+      const env = process.env.NODE_ENV || 'development';
       appdir.writeConfigFileSync('config.' + env + '.json', {
         cfgEnv: 'applied',
       });
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
-        var appConfig = instructions.application;
+        const instructions = context.instructions;
+        const appConfig = instructions.application;
 
         expect(appConfig).to.have.property('cfgLocal', 'applied');
         expect(appConfig).to.have.property('cfgEnv', 'applied');
 
-        var expectedLoadOrder = ['cfgLocal', 'cfgEnv'];
-        var actualLoadOrder = Object.keys(appConfig).filter(function(k) {
+        const expectedLoadOrder = ['cfgLocal', 'cfgEnv'];
+        const actualLoadOrder = Object.keys(appConfig).filter(function(k) {
           return expectedLoadOrder.indexOf(k) !== -1;
         });
 
@@ -765,13 +765,13 @@ describe('compiler', function() {
       appdir.createConfigFilesSync();
       appdir.writeFileSync(
         'config.local.js',
-        'module.exports = { fromJs: true };'
+        'module.exports = { fromJs: true };',
       );
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
-        var appConfig = instructions.application;
+        const instructions = context.instructions;
+        const appConfig = instructions.application;
 
         expect(appConfig).to.have.property('fromJs', true);
         done();
@@ -781,11 +781,11 @@ describe('compiler', function() {
     it('supports `appConfigRootDir` option', function(done) {
       appdir.createConfigFilesSync({port: 3000});
 
-      var customDir = path.resolve(appdir.PATH, 'custom');
+      const customDir = path.resolve(appdir.PATH, 'custom');
       fs.mkdirsSync(customDir);
       fs.renameSync(
         path.resolve(appdir.PATH, 'config.json'),
-        path.resolve(customDir, 'config.json')
+        path.resolve(customDir, 'config.json'),
       );
 
       boot.compile(
@@ -795,22 +795,22 @@ describe('compiler', function() {
         },
         function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
 
           expect(instructions.application).to.have.property('port');
           done();
-        }
+        },
       );
     });
 
     it('supports `dsRootDir` option', function(done) {
       appdir.createConfigFilesSync();
 
-      var customDir = path.resolve(appdir.PATH, 'custom');
+      const customDir = path.resolve(appdir.PATH, 'custom');
       fs.mkdirsSync(customDir);
       fs.renameSync(
         path.resolve(appdir.PATH, 'datasources.json'),
-        path.resolve(customDir, 'datasources.json')
+        path.resolve(customDir, 'datasources.json'),
       );
 
       boot.compile(
@@ -820,11 +820,11 @@ describe('compiler', function() {
         },
         function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
 
           expect(instructions.dataSources).to.have.property('db');
           done();
-        }
+        },
       );
     });
 
@@ -841,24 +841,24 @@ describe('compiler', function() {
         },
         function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
 
           expect(instructions.models).to.have.length(1);
           expect(instructions.models[0]).to.have.property('name', 'foo');
           done();
-        }
+        },
       );
     });
 
     it('includes boot/*.js scripts', function(done) {
       appdir.createConfigFilesSync();
-      var initJs = appdir.writeFileSync(
+      const initJs = appdir.writeFileSync(
         'boot/init.js',
-        'module.exports = function(app) { app.fnCalled = true; };'
+        'module.exports = function(app) { app.fnCalled = true; };',
       );
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
         expect(instructions.bootScripts).to.eql([initJs]);
         done();
       });
@@ -866,9 +866,9 @@ describe('compiler', function() {
 
     it('supports `bootDirs` option', function(done) {
       appdir.createConfigFilesSync();
-      var initJs = appdir.writeFileSync(
+      const initJs = appdir.writeFileSync(
         'custom-boot/init.js',
-        'module.exports = function(app) { app.fnCalled = true; };'
+        'module.exports = function(app) { app.fnCalled = true; };',
       );
       boot.compile(
         {
@@ -877,18 +877,18 @@ describe('compiler', function() {
         },
         function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
           expect(instructions.bootScripts).to.eql([initJs]);
           done();
-        }
+        },
       );
     });
 
     it('should resolve relative path in `bootDirs`', function(done) {
       appdir.createConfigFilesSync();
-      var initJs = appdir.writeFileSync(
+      const initJs = appdir.writeFileSync(
         'custom-boot/init.js',
-        'module.exports = function(app) { app.fnCalled = true; };'
+        'module.exports = function(app) { app.fnCalled = true; };',
       );
       boot.compile(
         {
@@ -897,16 +897,16 @@ describe('compiler', function() {
         },
         function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
           expect(instructions.bootScripts).to.eql([initJs]);
           done();
-        }
+        },
       );
     });
 
     it('should resolve non-relative path in `bootDirs`', function(done) {
       appdir.createConfigFilesSync();
-      var initJs = appdir.writeFileSync('custom-boot/init.js', '');
+      const initJs = appdir.writeFileSync('custom-boot/init.js', '');
       boot.compile(
         {
           appRootDir: appdir.PATH,
@@ -914,10 +914,10 @@ describe('compiler', function() {
         },
         function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
           expect(instructions.bootScripts).to.eql([initJs]);
           done();
-        }
+        },
       );
     });
 
@@ -931,17 +931,17 @@ describe('compiler', function() {
         },
         function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
           expect(instructions.bootScripts).to.have.length(0);
           done();
-        }
+        },
       );
     });
 
     it('prefers coffeescript over json in `appRootDir/bootDir`',
       function(done) {
         appdir.createConfigFilesSync();
-        var coffee = appdir.writeFileSync('./custom-boot/init.coffee', '');
+        const coffee = appdir.writeFileSync('./custom-boot/init.coffee', '');
         appdir.writeFileSync('./custom-boot/init.json', {});
 
         boot.compile(
@@ -951,17 +951,17 @@ describe('compiler', function() {
           },
           function(err, context) {
             if (err) return done(err);
-            var instructions = context.instructions;
+            const instructions = context.instructions;
             expect(instructions.bootScripts).to.eql([coffee]);
             done();
-          }
+          },
         );
       });
 
     it('prefers coffeescript over json in `bootDir` non-relative path',
       function(done) {
         appdir.createConfigFilesSync();
-        var coffee = appdir.writeFileSync('custom-boot/init.coffee', '');
+        const coffee = appdir.writeFileSync('custom-boot/init.coffee', '');
         appdir.writeFileSync('custom-boot/init.json', '');
 
         boot.compile(
@@ -971,18 +971,18 @@ describe('compiler', function() {
           },
           function(err, context) {
             if (err) return done(err);
-            var instructions = context.instructions;
+            const instructions = context.instructions;
             expect(instructions.bootScripts).to.eql([coffee]);
             done();
-          }
+          },
         );
       });
 
     it('supports `bootScripts` option', function(done) {
       appdir.createConfigFilesSync();
-      var initJs = appdir.writeFileSync(
+      const initJs = appdir.writeFileSync(
         'custom-boot/init.js',
-        'module.exports = function(app) { app.fnCalled = true; };'
+        'module.exports = function(app) { app.fnCalled = true; };',
       );
       boot.compile(
         {
@@ -991,18 +991,18 @@ describe('compiler', function() {
         },
         function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
           expect(instructions.bootScripts).to.eql([initJs]);
           done();
-        }
+        },
       );
     });
 
     it('should remove duplicate scripts', function(done) {
       appdir.createConfigFilesSync();
-      var initJs = appdir.writeFileSync(
+      const initJs = appdir.writeFileSync(
         'custom-boot/init.js',
-        'module.exports = function(app) { app.fnCalled = true; };'
+        'module.exports = function(app) { app.fnCalled = true; };',
       );
       boot.compile(
         {
@@ -1012,18 +1012,18 @@ describe('compiler', function() {
         },
         function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
           expect(instructions.bootScripts).to.eql([initJs]);
           done();
-        }
+        },
       );
     });
 
     it('should resolve relative path in `bootScripts`', function(done) {
       appdir.createConfigFilesSync();
-      var initJs = appdir.writeFileSync(
+      const initJs = appdir.writeFileSync(
         'custom-boot/init.js',
-        'module.exports = function(app) { app.fnCalled = true; };'
+        'module.exports = function(app) { app.fnCalled = true; };',
       );
       boot.compile(
         {
@@ -1032,16 +1032,16 @@ describe('compiler', function() {
         },
         function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
           expect(instructions.bootScripts).to.eql([initJs]);
           done();
-        }
+        },
       );
     });
 
     it('should resolve non-relative path in `bootScripts`', function(done) {
       appdir.createConfigFilesSync();
-      var initJs = appdir.writeFileSync('custom-boot/init.js', '');
+      const initJs = appdir.writeFileSync('custom-boot/init.js', '');
       boot.compile(
         {
           appRootDir: appdir.PATH,
@@ -1049,16 +1049,16 @@ describe('compiler', function() {
         },
         function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
           expect(instructions.bootScripts).to.eql([initJs]);
           done();
-        }
+        },
       );
     });
 
     it('resolves missing extensions in `bootScripts`', function(done) {
       appdir.createConfigFilesSync();
-      var initJs = appdir.writeFileSync('custom-boot/init.js', '');
+      const initJs = appdir.writeFileSync('custom-boot/init.js', '');
       boot.compile(
         {
           appRootDir: appdir.PATH,
@@ -1066,17 +1066,17 @@ describe('compiler', function() {
         },
         function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
           expect(instructions.bootScripts).to.eql([initJs]);
           done();
-        }
+        },
       );
     });
 
     it('resolves missing extensions in `bootScripts` in module relative path',
       function(done) {
         appdir.createConfigFilesSync();
-        var initJs = appdir.writeFileSync('node_modules/custom-boot/init.js',
+        const initJs = appdir.writeFileSync('node_modules/custom-boot/init.js',
           '');
 
         boot.compile(
@@ -1086,16 +1086,19 @@ describe('compiler', function() {
           },
           function(err, context) {
             if (err) return done(err);
-            var instructions = context.instructions;
+            const instructions = context.instructions;
             expect(instructions.bootScripts).to.eql([initJs]);
             done();
-          }
+          },
         );
       });
 
     it('resolves module relative path for `bootScripts`', function(done) {
       appdir.createConfigFilesSync();
-      var initJs = appdir.writeFileSync('node_modules/custom-boot/init.js', '');
+      const initJs = appdir.writeFileSync(
+        'node_modules/custom-boot/init.js',
+        '',
+      );
       boot.compile(
         {
           appRootDir: appdir.PATH,
@@ -1103,16 +1106,16 @@ describe('compiler', function() {
         },
         function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
           expect(instructions.bootScripts).to.eql([initJs]);
           done();
-        }
+        },
       );
     });
 
     it('explores `bootScripts` in app relative path', function(done) {
       appdir.createConfigFilesSync();
-      var appJs = appdir.writeFileSync('./custom-boot/init.js', '');
+      const appJs = appdir.writeFileSync('./custom-boot/init.js', '');
 
       appdir.writeFileSync('node_modules/custom-boot/init.js', '');
 
@@ -1123,10 +1126,10 @@ describe('compiler', function() {
         },
         function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
           expect(instructions.bootScripts).to.eql([appJs]);
           done();
-        }
+        },
       );
     });
 
@@ -1136,7 +1139,7 @@ describe('compiler', function() {
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
         expect(instructions.bootScripts).to.not.have.property('models');
         done();
@@ -1150,7 +1153,7 @@ describe('compiler', function() {
           {},
           {
             foo: {properties: {name: 'string'}},
-          }
+          },
         );
 
         expectCompileToThrow(/unsupported 1\.x format/, done);
@@ -1163,7 +1166,7 @@ describe('compiler', function() {
           {},
           {
             Customer: {options: {base: 'User'}},
-          }
+          },
         );
 
         expectCompileToThrow(/unsupported 1\.x format/, done);
@@ -1175,14 +1178,14 @@ describe('compiler', function() {
         {},
         {
           Car: {dataSource: 'db'},
-        }
+        },
       );
       appdir.writeConfigFileSync('models/car.json', {name: 'Car'});
       appdir.writeFileSync('models/car.js', '');
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
         expect(instructions.models).to.have.length(1);
         expect(instructions.models[0]).to.eql({
@@ -1205,14 +1208,14 @@ describe('compiler', function() {
         {},
         {
           Car: {dataSource: 'db'},
-        }
+        },
       );
       appdir.writeConfigFileSync('models/car.json', {name: 'Car'});
       appdir.writeFileSync('models/car.coffee', '');
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
         expect(instructions.models).to.have.length(1);
         expect(instructions.models[0]).to.eql({
@@ -1235,7 +1238,7 @@ describe('compiler', function() {
         {},
         {
           Car: {dataSource: 'db'},
-        }
+        },
       );
       appdir.writeConfigFileSync('custom-models/car.json', {name: 'Car'});
       appdir.writeFileSync('custom-models/car.js', '');
@@ -1247,7 +1250,7 @@ describe('compiler', function() {
         },
         function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
 
           expect(instructions.models).to.have.length(1);
           expect(instructions.models[0]).to.eql({
@@ -1261,7 +1264,7 @@ describe('compiler', function() {
             sourceFile: path.resolve(appdir.PATH, 'custom-models', 'car.js'),
           });
           done();
-        }
+        },
       );
     });
 
@@ -1274,14 +1277,14 @@ describe('compiler', function() {
             sources: ['./custom-models'],
           },
           Car: {dataSource: 'db'},
-        }
+        },
       );
       appdir.writeConfigFileSync('custom-models/car.json', {name: 'Car'});
       appdir.writeFileSync('custom-models/car.js', '');
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
         expect(instructions.models).to.have.length(1);
         expect(instructions.models[0]).to.eql({
@@ -1304,7 +1307,7 @@ describe('compiler', function() {
         {},
         {
           User: {dataSource: 'db'},
-        }
+        },
       );
 
       boot.compile(
@@ -1317,7 +1320,7 @@ describe('compiler', function() {
         },
         function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
 
           expect(instructions.models).to.have.length(1);
           expect(instructions.models[0]).to.eql({
@@ -1329,7 +1332,7 @@ describe('compiler', function() {
             sourceFile: require.resolve('loopback/common/models/user.js'),
           });
           done();
-        }
+        },
       );
     });
 
@@ -1339,10 +1342,10 @@ describe('compiler', function() {
         {},
         {
           Car: {dataSource: 'db'},
-        }
+        },
       );
       appdir.writeConfigFileSync('custom-models/car.json', {name: 'Car'});
-      var appJS = appdir.writeFileSync('custom-models/car.js', '');
+      const appJS = appdir.writeFileSync('custom-models/car.js', '');
 
       boot.compile(
         {
@@ -1351,12 +1354,12 @@ describe('compiler', function() {
         },
         function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
 
           expect(instructions.models).to.have.length(1);
           expect(instructions.models[0].sourceFile).to.equal(appJS);
           done();
-        }
+        },
       );
     });
 
@@ -1367,12 +1370,12 @@ describe('compiler', function() {
           {},
           {
             Car: {dataSource: 'db'},
-          }
+          },
         );
         appdir.writeConfigFileSync('node_modules/custom-models/car.json', {
           name: 'Car',
         });
-        var appJS = appdir.writeFileSync('node_modules/custom-models/car.js',
+        const appJS = appdir.writeFileSync('node_modules/custom-models/car.js',
           '');
 
         boot.compile(
@@ -1382,12 +1385,12 @@ describe('compiler', function() {
           },
           function(err, context) {
             if (err) return done(err);
-            var instructions = context.instructions;
+            const instructions = context.instructions;
 
             expect(instructions.models).to.have.length(1);
             expect(instructions.models[0].sourceFile).to.equal(appJS);
             done();
-          }
+          },
         );
       });
 
@@ -1401,14 +1404,14 @@ describe('compiler', function() {
               sources: ['./custom-models'],
             },
             Car: {dataSource: 'db'},
-          }
+          },
         );
         appdir.writeConfigFileSync('custom-models/car.json', {name: 'Car'});
-        var appJS = appdir.writeFileSync('custom-models/car.js', '');
+        const appJS = appdir.writeFileSync('custom-models/car.js', '');
 
         boot.compile(appdir.PATH, function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
 
           expect(instructions.models).to.have.length(1);
           expect(instructions.models[0].sourceFile).to.equal(appJS);
@@ -1426,18 +1429,18 @@ describe('compiler', function() {
               sources: ['custom-models'],
             },
             Car: {dataSource: 'db'},
-          }
+          },
         );
         appdir.writeConfigFileSync('node_modules/custom-models/car.json', {
           name: 'Car',
         });
 
-        var appJS = appdir.writeFileSync('node_modules/custom-models/car.js',
+        const appJS = appdir.writeFileSync('node_modules/custom-models/car.js',
           '');
 
         boot.compile(appdir.PATH, function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
 
           expect(instructions.models).to.have.length(1);
           expect(instructions.models[0].sourceFile).to.equal(appJS);
@@ -1451,13 +1454,13 @@ describe('compiler', function() {
         {},
         {
           Car: {dataSource: 'db'},
-        }
+        },
       );
       appdir.writeConfigFileSync('models/car.json', {name: 'Car'});
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
         expect(instructions.models).to.eql([
           {
@@ -1481,16 +1484,16 @@ describe('compiler', function() {
         {},
         {
           Car: {dataSource: 'db'},
-        }
+        },
       );
       appdir.writeConfigFileSync('models/car.json', {name: 'Car'});
       appdir.writeConfigFileSync('models/bar.json', {name: 'Bar'});
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
-        var models = instructions.models.map(getNameProperty);
+        const models = instructions.models.map(getNameProperty);
         expect(models).to.eql(['Car']);
         done();
       });
@@ -1502,7 +1505,7 @@ describe('compiler', function() {
         {},
         {
           Car: {dataSource: 'db'},
-        }
+        },
       );
       appdir.writeConfigFileSync('models/car.json', {
         name: 'Car',
@@ -1514,9 +1517,9 @@ describe('compiler', function() {
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
-        var models = instructions.models;
-        var modelNames = models.map(getNameProperty);
+        const instructions = context.instructions;
+        const models = instructions.models;
+        const modelNames = models.map(getNameProperty);
 
         expect(modelNames).to.eql(['Vehicle', 'Car']);
         expect(models[0].config).to.equal(undefined);
@@ -1530,7 +1533,7 @@ describe('compiler', function() {
         {},
         {
           Car: {dataSource: 'db'},
-        }
+        },
       );
       appdir.writeConfigFileSync('models/car.json', {
         name: 'Car',
@@ -1539,9 +1542,9 @@ describe('compiler', function() {
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
-        var modelNames = instructions.models.map(getNameProperty);
+        const modelNames = instructions.models.map(getNameProperty);
         expect(modelNames).to.eql(['Car']);
         done();
       });
@@ -1555,7 +1558,7 @@ describe('compiler', function() {
           Vehicle: {dataSource: 'db'},
           FlyingCar: {dataSource: 'db'},
           Car: {dataSource: 'db'},
-        }
+        },
       );
       appdir.writeConfigFileSync('models/car.json', {
         name: 'Car',
@@ -1571,9 +1574,9 @@ describe('compiler', function() {
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
-        var modelNames = instructions.models.map(getNameProperty);
+        const modelNames = instructions.models.map(getNameProperty);
         expect(modelNames).to.eql(['Vehicle', 'Car', 'FlyingCar']);
         done();
       });
@@ -1586,7 +1589,7 @@ describe('compiler', function() {
         {
           Vehicle: {dataSource: 'db'},
           Car: {dataSource: 'db'},
-        }
+        },
       );
       appdir.writeConfigFileSync('models/car.json', {
         name: 'Car',
@@ -1606,15 +1609,15 @@ describe('compiler', function() {
         {},
         {
           Car: {dataSource: 'db'},
-        }
+        },
       );
       appdir.writeConfigFileSync('models/car.json', {});
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
-        var modelNames = instructions.models.map(getNameProperty);
+        const modelNames = instructions.models.map(getNameProperty);
         expect(modelNames).to.eql(['Car']);
         done();
       });
@@ -1627,15 +1630,15 @@ describe('compiler', function() {
           {},
           {
             OrderItem: {dataSource: 'db'},
-          }
+          },
         );
         appdir.writeConfigFileSync('models/order-item.json', {});
 
         boot.compile(appdir.PATH, function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
 
-          var modelNames = instructions.models.map(getNameProperty);
+          const modelNames = instructions.models.map(getNameProperty);
           expect(modelNames).to.eql(['OrderItem']);
           done();
         });
@@ -1648,15 +1651,15 @@ describe('compiler', function() {
           {},
           {
             OrderItem: {dataSource: 'db'},
-          }
+          },
         );
         appdir.writeConfigFileSync('models/order_item.json', {});
 
         boot.compile(appdir.PATH, function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
 
-          var modelNames = instructions.models.map(getNameProperty);
+          const modelNames = instructions.models.map(getNameProperty);
           expect(modelNames).to.eql(['OrderItem']);
           done();
         });
@@ -1669,15 +1672,15 @@ describe('compiler', function() {
           {},
           {
             OrderItem: {dataSource: 'db'},
-          }
+          },
         );
         appdir.writeConfigFileSync('models/order item.json', {});
 
         boot.compile(appdir.PATH, function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
 
-          var modelNames = instructions.models.map(getNameProperty);
+          const modelNames = instructions.models.map(getNameProperty);
           expect(modelNames).to.eql(['OrderItem']);
           done();
         });
@@ -1690,15 +1693,15 @@ describe('compiler', function() {
           {},
           {
             overrideCar: {dataSource: 'db'},
-          }
+          },
         );
         appdir.writeConfigFileSync('models/car.json', {name: 'overrideCar'});
 
         boot.compile(appdir.PATH, function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
 
-          var modelNames = instructions.models.map(getNameProperty);
+          const modelNames = instructions.models.map(getNameProperty);
           expect(modelNames).to.eql(['overrideCar']);
           done();
         });
@@ -1710,7 +1713,7 @@ describe('compiler', function() {
         {},
         {
           OrderItem: {dataSource: 'db'},
-        }
+        },
       );
 
       appdir.writeConfigFileSync('models/order-item.json', {
@@ -1725,11 +1728,11 @@ describe('compiler', function() {
           quantity: {type: 'number'},
         },
       });
-      var appJS = appdir.writeFileSync('models/orderItem.js', '');
+      const appJS = appdir.writeFileSync('models/orderItem.js', '');
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
         expect(instructions.models).to.eql([
           {
@@ -1756,7 +1759,7 @@ describe('compiler', function() {
         {},
         {
           customOrder: {dataSource: 'db'},
-        }
+        },
       );
 
       appdir.writeConfigFileSync('models/order1.json', {
@@ -1773,11 +1776,11 @@ describe('compiler', function() {
           quantity: {type: 'number'},
         },
       });
-      var appJS = appdir.writeFileSync('models/order2.js', '');
+      const appJS = appdir.writeFileSync('models/order2.js', '');
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
         expect(instructions.models).to.eql([
           {
@@ -1803,12 +1806,12 @@ describe('compiler', function() {
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
         instructions.application.modified = true;
 
         boot.compile(appdir.PATH, function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
           expect(instructions.application).to.not.have.property('modified');
           done();
         });
@@ -1818,7 +1821,7 @@ describe('compiler', function() {
     describe('for mixins', function() {
       describe(' - mixinDirs', function(done) {
         function verifyMixinIsFoundViaMixinDirs(sourceFile, mixinDirs, done) {
-          var appJS = appdir.writeFileSync(sourceFile, '');
+          const appJS = appdir.writeFileSync(sourceFile, '');
 
           boot.compile(
             {
@@ -1827,10 +1830,10 @@ describe('compiler', function() {
             },
             function(err, context) {
               if (err) return done(err);
-              var instructions = context.instructions;
+              const instructions = context.instructions;
               expect(instructions.mixins[0].sourceFile).to.eql(appJS);
               done();
-            }
+            },
           );
         }
 
@@ -1838,7 +1841,7 @@ describe('compiler', function() {
           verifyMixinIsFoundViaMixinDirs(
             'custom-mixins/other.js',
             ['./custom-mixins'],
-            done
+            done,
           );
         });
 
@@ -1846,7 +1849,7 @@ describe('compiler', function() {
           verifyMixinIsFoundViaMixinDirs(
             'custom-mixins/other.js',
             ['./custom-mixins'],
-            done
+            done,
           );
         });
 
@@ -1855,7 +1858,7 @@ describe('compiler', function() {
             verifyMixinIsFoundViaMixinDirs(
               'node_modules/custom-mixins/other.js',
               ['custom-mixins'],
-              done
+              done,
             );
           });
       });
@@ -1867,7 +1870,7 @@ describe('compiler', function() {
             {},
             {
               Car: {dataSource: 'db'},
-            }
+            },
           );
           appdir.writeConfigFileSync('models/car.json', {
             name: 'Car',
@@ -1878,9 +1881,9 @@ describe('compiler', function() {
         function verifyMixinIsFoundViaMixinSources(
           sourceFile,
           mixinSources,
-          done
+          done,
         ) {
-          var appJS = appdir.writeFileSync(sourceFile, '');
+          const appJS = appdir.writeFileSync(sourceFile, '');
 
           boot.compile(
             {
@@ -1889,10 +1892,10 @@ describe('compiler', function() {
             },
             function(err, context) {
               if (err) return done(err);
-              var instructions = context.instructions;
+              const instructions = context.instructions;
               expect(instructions.mixins[0].sourceFile).to.eql(appJS);
               done();
-            }
+            },
           );
         }
 
@@ -1900,7 +1903,7 @@ describe('compiler', function() {
           verifyMixinIsFoundViaMixinSources(
             'mixins/time-stamps.js',
             ['./mixins'],
-            done
+            done,
           );
         });
 
@@ -1908,7 +1911,7 @@ describe('compiler', function() {
           verifyMixinIsFoundViaMixinSources(
             'custom-mixins/time-stamps.js',
             ['./custom-mixins'],
-            done
+            done,
           );
         });
 
@@ -1917,7 +1920,7 @@ describe('compiler', function() {
             verifyMixinIsFoundViaMixinSources(
               'node_modules/custom-mixins/time-stamps.js',
               ['custom-mixins'],
-              done
+              done,
             );
           });
 
@@ -1932,13 +1935,16 @@ describe('compiler', function() {
               Car: {
                 dataSource: 'db',
               },
-            }
+            },
           );
 
-          var appJS = appdir.writeFileSync('custom-mixins/time-stamps.js', '');
+          const appJS = appdir.writeFileSync(
+            'custom-mixins/time-stamps.js',
+            '',
+          );
           boot.compile(appdir.PATH, function(err, context) {
             if (err) return done(err);
-            var instructions = context.instructions;
+            const instructions = context.instructions;
             expect(instructions.mixins[0].sourceFile).to.eql(appJS);
             done();
           });
@@ -1946,22 +1952,22 @@ describe('compiler', function() {
 
         it('sets by default `mixinSources` to `mixins` directory',
           function(done) {
-            var appJS = appdir.writeFileSync('mixins/time-stamps.js', '');
+            const appJS = appdir.writeFileSync('mixins/time-stamps.js', '');
             boot.compile(appdir.PATH, function(err, context) {
               if (err) return done(err);
-              var instructions = context.instructions;
+              const instructions = context.instructions;
               expect(instructions.mixins[0].sourceFile).to.eql(appJS);
               done();
             });
           });
 
         it('loads only mixins used by models', function(done) {
-          var appJS = appdir.writeFileSync('mixins/time-stamps.js', '');
+          const appJS = appdir.writeFileSync('mixins/time-stamps.js', '');
           appdir.writeFileSync('mixins/foo.js', '');
 
           boot.compile(appdir.PATH, function(err, context) {
             if (err) return done(err);
-            var instructions = context.instructions;
+            const instructions = context.instructions;
             expect(instructions.mixins).to.have.length(1);
             expect(instructions.mixins[0].sourceFile).to.eql(appJS);
             done();
@@ -1970,7 +1976,7 @@ describe('compiler', function() {
 
         it('loads mixins from model using mixin name in JSON file',
           function(done) {
-            var appJS = appdir.writeFileSync('mixins/time-stamps.js', '');
+            const appJS = appdir.writeFileSync('mixins/time-stamps.js', '');
             appdir.writeConfigFileSync('mixins/time-stamps.json', {
               name: 'Timestamping',
             });
@@ -1982,7 +1988,7 @@ describe('compiler', function() {
 
             boot.compile(appdir.PATH, function(err, context) {
               if (err) return done(err);
-              var instructions = context.instructions;
+              const instructions = context.instructions;
               expect(instructions.mixins).to.have.length(1);
               expect(instructions.mixins[0].sourceFile).to.eql(appJS);
               done();
@@ -1991,10 +1997,10 @@ describe('compiler', function() {
 
         it('loads mixin only once for dirs common to mixinDirs & mixinSources',
           function(done) {
-            var appJS = appdir.writeFileSync('custom-mixins/time-stamps.js',
+            const appJS = appdir.writeFileSync('custom-mixins/time-stamps.js',
               '');
 
-            var options = {
+            const options = {
               appRootDir: appdir.PATH,
               mixinDirs: ['./custom-mixins'],
               mixinSources: ['./custom-mixins'],
@@ -2002,7 +2008,7 @@ describe('compiler', function() {
 
             boot.compile(options, function(err, context) {
               if (err) return done(err);
-              var instructions = context.instructions;
+              const instructions = context.instructions;
               expect(instructions.mixins).to.have.length(1);
               expect(instructions.mixins[0].sourceFile).to.eql(appJS);
               done();
@@ -2012,9 +2018,12 @@ describe('compiler', function() {
         it('loads mixin from mixinSources, when it is also found in mixinDirs',
           function(done) {
             appdir.writeFileSync('mixinDir/time-stamps.js', '');
-            var appJS = appdir.writeFileSync('mixinSource/time-stamps.js', '');
+            const appJS = appdir.writeFileSync(
+              'mixinSource/time-stamps.js',
+              '',
+            );
 
-            var options = {
+            const options = {
               appRootDir: appdir.PATH,
               mixinDirs: ['./mixinDir'],
               mixinSources: ['./mixinSource'],
@@ -2022,7 +2031,7 @@ describe('compiler', function() {
 
             boot.compile(options, function(err, context) {
               if (err) return done(err);
-              var instructions = context.instructions;
+              const instructions = context.instructions;
               expect(instructions.mixins).to.have.length(1);
               expect(instructions.mixins[0].sourceFile).to.eql(appJS);
               done();
@@ -2031,16 +2040,16 @@ describe('compiler', function() {
 
         it('loads mixin from the most recent mixin definition', function(done) {
           appdir.writeFileSync('mixins1/time-stamps.js', '');
-          var mixins2 = appdir.writeFileSync('mixins2/time-stamps.js', '');
+          const mixins2 = appdir.writeFileSync('mixins2/time-stamps.js', '');
 
-          var options = {
+          const options = {
             appRootDir: appdir.PATH,
             mixinSources: ['./mixins1', './mixins2'],
           };
 
           boot.compile(options, function(err, context) {
             if (err) return done(err);
-            var instructions = context.instructions;
+            const instructions = context.instructions;
             expect(instructions.mixins).to.have.length(1);
             expect(instructions.mixins[0].sourceFile).to.eql(mixins2);
             done();
@@ -2049,7 +2058,7 @@ describe('compiler', function() {
       });
 
       describe('name normalization', function() {
-        var options;
+        let options;
         beforeEach(function() {
           options = {appRootDir: appdir.PATH, mixinDirs: ['./custom-mixins']};
 
@@ -2064,10 +2073,10 @@ describe('compiler', function() {
           options.normalization = 'classify';
           boot.compile(options, function(err, context) {
             if (err) return done(err);
-            var instructions = context.instructions;
+            const instructions = context.instructions;
 
-            var mixins = instructions.mixins;
-            var mixinNames = mixins.map(getNameProperty);
+            const mixins = instructions.mixins;
+            const mixinNames = mixins.map(getNameProperty);
 
             expect(mixinNames).to.eql([
               'CamelCase',
@@ -2084,10 +2093,10 @@ describe('compiler', function() {
           options.normalization = 'dasherize';
           boot.compile(options, function(err, context) {
             if (err) return done(err);
-            var instructions = context.instructions;
+            const instructions = context.instructions;
 
-            var mixins = instructions.mixins;
-            var mixinNames = mixins.map(getNameProperty);
+            const mixins = instructions.mixins;
+            const mixinNames = mixins.map(getNameProperty);
 
             expect(mixinNames).to.eql([
               'camel-case',
@@ -2101,16 +2110,16 @@ describe('compiler', function() {
         });
 
         it('supports custom function', function(done) {
-          var normalize = function(name) {
+          const normalize = function(name) {
             return name.toUpperCase();
           };
           options.normalization = normalize;
           boot.compile(options, function(err, context) {
             if (err) return done(err);
-            var instructions = context.instructions;
+            const instructions = context.instructions;
 
-            var mixins = instructions.mixins;
-            var mixinNames = mixins.map(getNameProperty);
+            const mixins = instructions.mixins;
+            const mixinNames = mixins.map(getNameProperty);
 
             expect(mixinNames).to.eql([
               'CAMELCASE',
@@ -2127,10 +2136,10 @@ describe('compiler', function() {
           options.normalization = 'none';
           boot.compile(options, function(err, context) {
             if (err) return done(err);
-            var instructions = context.instructions;
+            const instructions = context.instructions;
 
-            var mixins = instructions.mixins;
-            var mixinNames = mixins.map(getNameProperty);
+            const mixins = instructions.mixins;
+            const mixinNames = mixins.map(getNameProperty);
 
             expect(mixinNames).to.eql([
               'camelCase',
@@ -2147,10 +2156,10 @@ describe('compiler', function() {
           options.normalization = false;
           boot.compile(options, function(err, context) {
             if (err) return done(err);
-            var instructions = context.instructions;
+            const instructions = context.instructions;
 
-            var mixins = instructions.mixins;
-            var mixinNames = mixins.map(getNameProperty);
+            const mixins = instructions.mixins;
+            const mixinNames = mixins.map(getNameProperty);
 
             expect(mixinNames).to.eql([
               'camelCase',
@@ -2166,10 +2175,10 @@ describe('compiler', function() {
         it('defaults to classify', function(done) {
           boot.compile(options, function(err, context) {
             if (err) return done(err);
-            var instructions = context.instructions;
+            const instructions = context.instructions;
 
-            var mixins = instructions.mixins;
-            var mixinNames = mixins.map(getNameProperty);
+            const mixins = instructions.mixins;
+            const mixinNames = mixins.map(getNameProperty);
 
             expect(mixinNames).to.eql([
               'CamelCase',
@@ -2188,7 +2197,7 @@ describe('compiler', function() {
           expectCompileToThrow(
             /Invalid normalization format - "invalidFormat"/,
             options,
-            done
+            done,
           );
         });
       });
@@ -2197,13 +2206,13 @@ describe('compiler', function() {
         appdir.writeFileSync('mixins/foo.js', '');
         appdir.writeConfigFileSync('mixins/foo.json', {name: 'fooBar'});
 
-        var options = {
+        const options = {
           appRootDir: appdir.PATH,
           mixinDirs: ['./mixins'],
         };
         boot.compile(options, function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
 
           expect(instructions.mixins[0].name).to.eql('fooBar');
           done();
@@ -2211,7 +2220,7 @@ describe('compiler', function() {
       });
 
       it('extends definition from JSON with same file name', function(done) {
-        var appJS = appdir.writeFileSync('custom-mixins/foo-bar.js', '');
+        const appJS = appdir.writeFileSync('custom-mixins/foo-bar.js', '');
 
         appdir.writeConfigFileSync('custom-mixins/foo-bar.json', {
           description: 'JSON file name same as JS file name',
@@ -2220,14 +2229,14 @@ describe('compiler', function() {
           description: 'JSON file name same as normalized name of mixin',
         });
 
-        var options = {
+        const options = {
           appRootDir: appdir.PATH,
           mixinDirs: ['./custom-mixins'],
           normalization: 'classify',
         };
         boot.compile(options, function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
 
           expect(instructions.mixins).to.eql([
             {
@@ -2244,7 +2253,7 @@ describe('compiler', function() {
 
   describe('for middleware', function() {
     function testMiddlewareRegistration(middlewareId, sourceFile, done) {
-      var json = {
+      const json = {
         initial: {},
         custom: {},
       };
@@ -2257,7 +2266,7 @@ describe('compiler', function() {
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
         expect(instructions.middleware).to.eql({
           phases: ['initial', 'custom'],
@@ -2275,11 +2284,11 @@ describe('compiler', function() {
       });
     }
 
-    var sourceFileForUrlNotFound;
+    let sourceFileForUrlNotFound;
     beforeEach(function() {
       fs.copySync(SIMPLE_APP, appdir.PATH);
       sourceFileForUrlNotFound = require.resolve(
-        'loopback/server/middleware/url-not-found'
+        'loopback/server/middleware/url-not-found',
       );
     });
 
@@ -2287,7 +2296,7 @@ describe('compiler', function() {
       testMiddlewareRegistration(
         'loopback/server/middleware/url-not-found',
         sourceFileForUrlNotFound,
-        done
+        done,
       );
     });
 
@@ -2295,12 +2304,12 @@ describe('compiler', function() {
       testMiddlewareRegistration(
         'loopback#url-not-found',
         sourceFileForUrlNotFound,
-        done
+        done,
       );
     });
 
     it('supports `middlewareRootDir` option', function(done) {
-      var middlewareJson = {
+      const middlewareJson = {
         initial: {},
         custom: {
           'loopback/server/middleware/url-not-found': {
@@ -2308,11 +2317,11 @@ describe('compiler', function() {
           },
         },
       };
-      var customDir = path.resolve(appdir.PATH, 'custom');
+      const customDir = path.resolve(appdir.PATH, 'custom');
       fs.mkdirsSync(customDir);
       fs.writeJsonSync(
         path.resolve(customDir, 'middleware.json'),
-        middlewareJson
+        middlewareJson,
       );
       boot.compile(
         {
@@ -2320,7 +2329,7 @@ describe('compiler', function() {
           middlewareRootDir: customDir,
         },
         function(err, context) {
-          var instructions = context.instructions;
+          const instructions = context.instructions;
           expect(instructions.middleware).to.eql({
             phases: ['initial', 'custom'],
             middleware: [
@@ -2334,7 +2343,7 @@ describe('compiler', function() {
             ],
           });
           done();
-        }
+        },
       );
     });
 
@@ -2396,7 +2405,7 @@ describe('compiler', function() {
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
         expect(instructions.middleware).to.eql({
           phases: ['routes'],
@@ -2434,7 +2443,7 @@ describe('compiler', function() {
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
         expectFirstMiddlewareParams(instructions).to.eql({
           key: 'custom value',
@@ -2464,11 +2473,11 @@ describe('compiler', function() {
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
         expect(instructions.middleware.middleware[0].config).to.have.property(
           'enabled',
-          false
+          false,
         );
         done();
       });
@@ -2477,7 +2486,7 @@ describe('compiler', function() {
     function verifyMiddlewareConfig(done) {
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
         expect(instructions.middleware.middleware).to.eql([
           {
@@ -2604,7 +2613,7 @@ describe('compiler', function() {
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
         expect(instructions.middleware.middleware).to.eql([
           {
@@ -2655,7 +2664,7 @@ describe('compiler', function() {
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
         expect(instructions.middleware.middleware).to.eql([
           {
@@ -2695,7 +2704,7 @@ describe('compiler', function() {
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
         expect(instructions.middleware.phases, 'phases').to.eql([
           'initial',
@@ -2704,7 +2713,7 @@ describe('compiler', function() {
         expect(instructions.middleware.middleware, 'middleware').to.eql([
           {
             sourceFile: require.resolve(
-              'loopback/server/middleware/url-not-found'
+              'loopback/server/middleware/url-not-found',
             ),
             config: {
               phase: 'custom:before',
@@ -2733,7 +2742,7 @@ describe('compiler', function() {
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
         expect(instructions.middleware.middleware).to.eql([
           {
@@ -2764,10 +2773,10 @@ describe('compiler', function() {
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
         expect(instructions.middleware.middleware[0].sourceFile).to.equal(
-          require.resolve('loopback/server/middleware/url-not-found')
+          require.resolve('loopback/server/middleware/url-not-found'),
         );
         done();
       });
@@ -2782,14 +2791,14 @@ describe('compiler', function() {
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
         expect(instructions.middleware.middleware[0].sourceFile).to.equal(
-          path.resolve(appdir.PATH, './middleware/index.js')
+          path.resolve(appdir.PATH, './middleware/index.js'),
         );
         expect(instructions.middleware.middleware[0]).have.property(
           'fragment',
-          'myMiddleware'
+          'myMiddleware',
         );
         done();
       });
@@ -2805,25 +2814,25 @@ describe('compiler', function() {
 
         boot.compile(appdir.PATH, function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
 
           expect(instructions.middleware.middleware[0]).have.property(
             'sourceFile',
-            pathWithoutIndex(require.resolve('loopback'))
+            pathWithoutIndex(require.resolve('loopback')),
           );
           expect(instructions.middleware.middleware[0]).have.property(
             'fragment',
-            'errorHandler'
+            'errorHandler',
           );
           done();
         });
       });
 
     it('resolves modules relative to appRootDir', function(done) {
-      var HANDLER_FILE = 'node_modules/handler/index.js';
+      const HANDLER_FILE = 'node_modules/handler/index.js';
       appdir.writeFileSync(
         HANDLER_FILE,
-        'module.exports = function(req, res, next) { next(); }'
+        'module.exports = function(req, res, next) { next(); }',
       );
 
       appdir.writeConfigFileSync('middleware.json', {
@@ -2834,18 +2843,18 @@ describe('compiler', function() {
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
         expect(instructions.middleware.middleware[0]).have.property(
           'sourceFile',
-          pathWithoutIndex(appdir.resolve(HANDLER_FILE))
+          pathWithoutIndex(appdir.resolve(HANDLER_FILE)),
         );
         done();
       });
     });
 
     it('prefers appRootDir over node_modules for middleware', function(done) {
-      var appJS = appdir.writeFileSync('./my-middleware.js', '');
+      const appJS = appdir.writeFileSync('./my-middleware.js', '');
       appdir.writeFileSync('node_modules/my-middleware.js', '');
       appdir.writeConfigFileSync('middleware.json', {
         routes: {
@@ -2855,12 +2864,12 @@ describe('compiler', function() {
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
         expect(instructions.middleware.middleware).to.have.length(1);
         expect(instructions.middleware.middleware[0]).have.property(
           'sourceFile',
-          appJS
+          appJS,
         );
         done();
       });
@@ -2869,7 +2878,7 @@ describe('compiler', function() {
     it('does not treat module relative path as `appRootDir` relative',
       function(done) {
         appdir.writeFileSync('./my-middleware.js', '');
-        var moduleJS = appdir.writeFileSync('node_modules/my-middleware.js',
+        const moduleJS = appdir.writeFileSync('node_modules/my-middleware.js',
           '');
         appdir.writeConfigFileSync('middleware.json', {
           routes: {
@@ -2879,19 +2888,19 @@ describe('compiler', function() {
 
         boot.compile(appdir.PATH, function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
 
           expect(instructions.middleware.middleware).to.have.length(1);
           expect(instructions.middleware.middleware[0]).have.property(
             'sourceFile',
-            moduleJS
+            moduleJS,
           );
           done();
         });
       });
 
     it('loads middleware from coffeescript in appRootdir', function(done) {
-      var coffee = appdir.writeFileSync('my-middleware.coffee', '');
+      const coffee = appdir.writeFileSync('my-middleware.coffee', '');
       appdir.writeConfigFileSync('middleware.json', {
         routes: {
           './my-middleware': {},
@@ -2900,20 +2909,20 @@ describe('compiler', function() {
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
         expect(instructions.middleware.middleware[0]).have.property(
           'sourceFile',
-          coffee
+          coffee,
         );
         done();
       });
     });
 
     it('loads coffeescript from middleware under node_modules', function(done) {
-      var file = appdir.writeFileSync(
+      const file = appdir.writeFileSync(
         'node_modules/my-middleware/index.coffee',
-        ''
+        '',
       );
       appdir.writeFileSync('node_modules/my-middleware/index.json', '');
       appdir.writeConfigFileSync('middleware.json', {
@@ -2924,12 +2933,12 @@ describe('compiler', function() {
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
         expect(instructions.middleware.middleware).to.have.length(1);
         expect(instructions.middleware.middleware[0]).have.property(
           'sourceFile',
-          pathWithoutIndex(file)
+          pathWithoutIndex(file),
         );
         done();
       });
@@ -2937,7 +2946,7 @@ describe('compiler', function() {
 
     it('prefers coffeescript over json for relative middleware path',
       function(done) {
-        var coffee = appdir.writeFileSync('my-middleware.coffee', '');
+        const coffee = appdir.writeFileSync('my-middleware.coffee', '');
         appdir.writeFileSync('my-middleware.json', '');
         appdir.writeConfigFileSync('middleware.json', {
           routes: {
@@ -2947,12 +2956,12 @@ describe('compiler', function() {
 
         boot.compile(appdir.PATH, function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
 
           expect(instructions.middleware.middleware).to.have.length(1);
           expect(instructions.middleware.middleware[0]).have.property(
             'sourceFile',
-            coffee
+            coffee,
           );
           done();
         });
@@ -2960,9 +2969,9 @@ describe('compiler', function() {
 
     it('prefers coffeescript over json for module relative middleware path',
       function(done) {
-        var coffee = appdir.writeFileSync(
+        const coffee = appdir.writeFileSync(
           'node_modules/my-middleware.coffee',
-          ''
+          '',
         );
         appdir.writeFileSync('node_modules/my-middleware.json', '');
         appdir.writeConfigFileSync('middleware.json', {
@@ -2973,25 +2982,25 @@ describe('compiler', function() {
 
         boot.compile(appdir.PATH, function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
 
           expect(instructions.middleware.middleware).to.have.length(1);
           expect(instructions.middleware.middleware[0]).have.property(
             'sourceFile',
-            coffee
+            coffee,
           );
           done();
         });
       });
 
     it('ignores sourcmap files when loading middleware', function(done) {
-      var middleware = appdir.writeFileSync(
+      const middleware = appdir.writeFileSync(
         'my-middleware.js',
-        '// I am the middleware'
+        '// I am the middleware',
       );
-      var sourcemap = appdir.writeFileSync(
+      const sourcemap = appdir.writeFileSync(
         'my-middleware.js.map',
-        '// I am a sourcemap'
+        '// I am a sourcemap',
       );
       appdir.writeConfigFileSync('middleware.json', {
         routes: {
@@ -3001,20 +3010,20 @@ describe('compiler', function() {
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
         expect(instructions.middleware.middleware[0]).have.property(
           'sourceFile',
-          middleware
+          middleware,
         );
         done();
       });
     });
 
     describe('config with relative paths in params', function() {
-      var RELATIVE_PATH_PARAMS = ['$!./here', '$!../there'];
+      const RELATIVE_PATH_PARAMS = ['$!./here', '$!../there'];
 
-      var absolutePathParams;
+      let absolutePathParams;
       beforeEach(function resolveRelativePathParams() {
         absolutePathParams = RELATIVE_PATH_PARAMS.map(function(p) {
           return appdir.resolve(p.slice(2));
@@ -3026,7 +3035,7 @@ describe('compiler', function() {
 
         boot.compile(appdir.PATH, function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
 
           expectFirstMiddlewareParams(instructions).to.eql(absolutePathParams);
           done();
@@ -3042,7 +3051,7 @@ describe('compiler', function() {
 
         boot.compile(appdir.PATH, function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
 
           expectFirstMiddlewareParams(instructions).to.eql({
             path: absolutePathParams[0],
@@ -3056,10 +3065,10 @@ describe('compiler', function() {
 
         boot.compile(appdir.PATH, function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
 
           expectFirstMiddlewareParams(instructions).to.eql(
-            absolutePathParams[0]
+            absolutePathParams[0],
           );
           done();
         });
@@ -3077,7 +3086,7 @@ describe('compiler', function() {
 
         boot.compile(appdir.PATH, function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
 
           expectFirstMiddlewareParams(instructions).to.eql({
             nestedObject: {
@@ -3091,12 +3100,12 @@ describe('compiler', function() {
 
       it('does not convert values not starting with `./` or `../`',
         function(done) {
-          var PARAMS = ['$!.somerc', '$!/root', '$!hello!'];
+          const PARAMS = ['$!.somerc', '$!/root', '$!hello!'];
           givenMiddlewareEntrySync({params: PARAMS});
 
           boot.compile(appdir.PATH, function(err, context) {
             if (err) return done(err);
-            var instructions = context.instructions;
+            const instructions = context.instructions;
 
             expectFirstMiddlewareParams(instructions).to.eql(PARAMS);
             done();
@@ -3115,16 +3124,16 @@ describe('compiler', function() {
         debug: {local: 'applied'},
       });
 
-      var env = process.env.NODE_ENV || 'development';
+      const env = process.env.NODE_ENV || 'development';
       appdir.writeConfigFileSync('component-config.' + env + '.json', {
         debug: {env: 'applied'},
       });
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
 
-        var component = instructions.components[0];
+        const component = instructions.components[0];
         expect(component).to.eql({
           sourceFile: require.resolve('debug'),
           config: {
@@ -3138,16 +3147,16 @@ describe('compiler', function() {
     });
 
     it('supports `componentRootDir` option', function(done) {
-      var componentJson = {
+      const componentJson = {
         debug: {
           option: 'value',
         },
       };
-      var customDir = path.resolve(appdir.PATH, 'custom');
+      const customDir = path.resolve(appdir.PATH, 'custom');
       fs.mkdirsSync(customDir);
       fs.writeJsonSync(
         path.resolve(customDir, 'component-config.json'),
-        componentJson
+        componentJson,
       );
 
       boot.compile(
@@ -3157,8 +3166,8 @@ describe('compiler', function() {
         },
         function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
-          var component = instructions.components[0];
+          const instructions = context.instructions;
+          const component = instructions.components[0];
           expect(component).to.eql({
             sourceFile: require.resolve('debug'),
             config: {
@@ -3166,7 +3175,7 @@ describe('compiler', function() {
             },
           });
           done();
-        }
+        },
       );
     });
 
@@ -3174,11 +3183,11 @@ describe('compiler', function() {
       appdir.writeConfigFileSync('./component-config.json', {
         './index': {},
       });
-      var appJS = appdir.writeConfigFileSync('index.js', '');
+      const appJS = appdir.writeConfigFileSync('index.js', '');
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
         expect(instructions.components[0]).have.property('sourceFile', appJS);
         done();
       });
@@ -3188,14 +3197,14 @@ describe('compiler', function() {
       appdir.writeConfigFileSync('component-config.json', {
         mycomponent: {},
       });
-      var js = appdir.writeConfigFileSync(
+      const js = appdir.writeConfigFileSync(
         'node_modules/mycomponent/index.js',
-        ''
+        '',
       );
 
       boot.compile(appdir.PATH, function(err, context) {
         if (err) return done(err);
-        var instructions = context.instructions;
+        const instructions = context.instructions;
         expect(instructions.components[0]).have.property('sourceFile', js);
         done();
       });
@@ -3210,7 +3219,7 @@ describe('compiler', function() {
 
         expectCompileToThrow(
           'Cannot resolve path "my-component/component.js"',
-          done
+          done,
         );
       });
 
@@ -3220,17 +3229,17 @@ describe('compiler', function() {
           './component': {},
         });
 
-        var coffee = appdir.writeFileSync('component.coffee', '');
+        const coffee = appdir.writeFileSync('component.coffee', '');
         appdir.writeFileSync('component.json', '');
 
         boot.compile(appdir.PATH, function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
 
           expect(instructions.components).to.have.length(1);
           expect(instructions.components[0]).have.property(
             'sourceFile',
-            coffee
+            coffee,
           );
           done();
         });
@@ -3242,17 +3251,20 @@ describe('compiler', function() {
           component: {},
         });
 
-        var coffee = appdir.writeFileSync('node_modules/component.coffee', '');
+        const coffee = appdir.writeFileSync(
+          'node_modules/component.coffee',
+          '',
+        );
         appdir.writeFileSync('node_modules/component.json', '');
 
         boot.compile(appdir.PATH, function(err, context) {
           if (err) return done(err);
-          var instructions = context.instructions;
+          const instructions = context.instructions;
 
           expect(instructions.components).to.have.length(1);
           expect(instructions.components[0]).have.property(
             'sourceFile',
-            coffee
+            coffee,
           );
           done();
         });
@@ -3280,7 +3292,7 @@ function expectFirstMiddlewareParams(instructions) {
 function pathWithoutExtension(value) {
   return path.join(
     path.dirname(value),
-    path.basename(value, path.extname(value))
+    path.basename(value, path.extname(value)),
   );
 }
 
diff --git a/test/executor.test.js b/test/executor.test.js
index 529959a..fd6ad7c 100644
--- a/test/executor.test.js
+++ b/test/executor.test.js
@@ -5,27 +5,27 @@
 
 'use strict';
 
-var async = require('async');
-var boot = require('../');
-var path = require('path');
-var loopback = require('loopback');
-var assert = require('assert');
+const async = require('async');
+const boot = require('../');
+const path = require('path');
+const loopback = require('loopback');
+const assert = require('assert');
 
-var chai = require('chai');
-var dirtyChai = require('dirty-chai');
-var expect = chai.expect;
+const chai = require('chai');
+const dirtyChai = require('dirty-chai');
+const expect = chai.expect;
 chai.use(dirtyChai);
 
-var fs = require('fs-extra');
-var sandbox = require('./helpers/sandbox');
-var appdir = require('./helpers/appdir');
-var supertest = require('supertest');
-var os = require('os');
+const fs = require('fs-extra');
+const sandbox = require('./helpers/sandbox');
+const appdir = require('./helpers/appdir');
+const supertest = require('supertest');
+const os = require('os');
 
-var SIMPLE_APP = path.join(__dirname, 'fixtures', 'simple-app');
-var ENV_APP = path.join(__dirname, 'fixtures', 'env-app');
+const SIMPLE_APP = path.join(__dirname, 'fixtures', 'simple-app');
+const ENV_APP = path.join(__dirname, 'fixtures', 'env-app');
 
-var app;
+let app;
 
 describe('executor', function() {
   beforeEach(sandbox.reset);
@@ -43,7 +43,7 @@ describe('executor', function() {
     delete process.bootFlags;
   });
 
-  var dummyInstructions = someInstructions({
+  const dummyInstructions = someInstructions({
     application: {
       port: 0,
       host: '127.0.0.1',
@@ -134,7 +134,7 @@ describe('executor', function() {
 
       expect(app.models.Customer).to.exist();
       expect(app.models.Customer.settings._customized).to.be.equal('Customer');
-      var UserModel = app.registry.getModel('User');
+      const UserModel = app.registry.getModel('User');
       expect(UserModel.settings._customized).to.equal('Base');
       done();
     });
@@ -232,7 +232,7 @@ describe('executor', function() {
   });
 
   it('throws on bad require() call inside boot script', function(done) {
-    var file = appdir.writeFileSync('boot/badScript.js',
+    const file = appdir.writeFileSync('boot/badScript.js',
       'require("doesnt-exist"); module.exports = {};');
 
     boot.execute(app, someInstructions({bootScripts: [file]}),
@@ -261,7 +261,7 @@ describe('executor', function() {
       // loopback-datasource-juggler quirk:
       // Model.dataSources has modelBuilder as the default value,
       // therefore it's not enough to assert a false-y value
-      var actual = loopback.Email.dataSource instanceof loopback.DataSource ?
+      const actual = loopback.Email.dataSource instanceof loopback.DataSource ?
         'attached' : 'not attached';
       expect(actual).to.equal('not attached');
       done();
@@ -269,10 +269,10 @@ describe('executor', function() {
   });
 
   it('skips definition of already defined LoopBack models', function(done) {
-    var builtinModel = {
+    const builtinModel = {
       name: 'User',
       definition: fs.readJsonSync(
-        require.resolve('loopback/common/models/user.json')
+        require.resolve('loopback/common/models/user.json'),
       ),
       config: {dataSource: 'db'},
       sourceFile: require.resolve('loopback/common/models/user.js'),
@@ -412,7 +412,7 @@ describe('executor', function() {
     });
 
   describe('for mixins', function() {
-    var options;
+    let options;
     beforeEach(function() {
       appdir.writeFileSync('custom-mixins/example.js',
         'module.exports = ' +
@@ -436,8 +436,8 @@ describe('executor', function() {
         options.mixinDirs = ['./custom-mixins'];
         boot(app, options, function(err) {
           if (err) return done(err);
-          var modelBuilder = app.registry.modelBuilder;
-          var registry = modelBuilder.mixins.mixins;
+          const modelBuilder = app.registry.modelBuilder;
+          const registry = modelBuilder.mixins.mixins;
           expect(Object.keys(registry)).to.eql(['Example', 'Timestamping']);
           done();
         });
@@ -449,8 +449,8 @@ describe('executor', function() {
         boot(app, options, function(err) {
           if (err) return done(err);
 
-          var modelBuilder = app.registry.modelBuilder;
-          var registry = modelBuilder.mixins.mixins;
+          const modelBuilder = app.registry.modelBuilder;
+          const registry = modelBuilder.mixins.mixins;
           expect(Object.keys(registry)).to.eql(['Example', 'Timestamping']);
           done();
         });
@@ -581,7 +581,7 @@ describe('executor', function() {
     });
 
     it('should respect named pipes port values in ENV', function(done) {
-      var NAMED_PORT = '\\.\\pipe\\test';
+      const NAMED_PORT = '\\.\\pipe\\test';
       process.env.PORT = NAMED_PORT;
       boot.execute(app, someInstructions({application: {port: 3000}}),
         function(err) {
@@ -627,8 +627,7 @@ describe('executor', function() {
     it('dynamic variable from `env var` should have' +
       ' precedence over app.get()', function(done) {
       process.env.restApiRoot = '/url-from-env-var';
-      var bootInstructions;
-      bootInstructions = simpleMiddlewareConfig('routes',
+      const bootInstructions = simpleMiddlewareConfig('routes',
         {path: '${restApiRoot}'});
       bootInstructions.application = {restApiRoot: '/url-from-config'};
       boot.execute(app, someInstructions(bootInstructions), function(err) {
@@ -665,7 +664,7 @@ describe('executor', function() {
         supertest(app).get('/').end(function(err, res) {
           if (err) return done(err);
           expect(res.body.paths).to.eql(
-            [app.get('restApiRoot')]
+            [app.get('restApiRoot')],
           );
           done();
         });
@@ -721,10 +720,10 @@ describe('executor', function() {
     });
 
     it('should not parse invalid config variables', function(done) {
-      var invalidDataTypes = [undefined, function() {
+      const invalidDataTypes = [undefined, function() {
       }];
       async.each(invalidDataTypes, function(invalidDataType, cb) {
-        var config = simpleMiddlewareConfig('routes', {
+        const config = simpleMiddlewareConfig('routes', {
           path: invalidDataType,
         });
         boot.execute(app, config, function(err) {
@@ -742,7 +741,7 @@ describe('executor', function() {
     });
 
     it('should parse valid config variables', function(done) {
-      var config = simpleMiddlewareConfig('routes', {
+      const config = simpleMiddlewareConfig('routes', {
         props: ['a', '${vVar}', 1, true, function() {
         }, {x: 1, y: '${y}'}],
       });
@@ -759,11 +758,11 @@ describe('executor', function() {
     });
 
     it('should preserve object prototypes', function(done) {
-      var config = simpleMiddlewareConfig(
+      const config = simpleMiddlewareConfig(
         'routes',
         // IMPORTANT we need more than one item to trigger the original issue
         [/^\/foobar/, /^\/another/],
-        {}
+        {},
       );
       boot.execute(app, config, function(err) {
         if (err) return done(err);
@@ -783,7 +782,7 @@ describe('executor', function() {
 
     it('should parse a simple config variable', function(done) {
       boot.execute(app, simpleComponentConfig(
-        {path: '${restApiRoot}'}
+        {path: '${restApiRoot}'},
       ), function(err) {
         if (err) return done(err);
 
@@ -796,12 +795,12 @@ describe('executor', function() {
     });
 
     it('should parse config from `env-var` and `config`', function(done) {
-      var bootInstructions = simpleComponentConfig(
+      const bootInstructions = simpleComponentConfig(
         {
           path: '${restApiRoot}',
           fromConfig: '${DYNAMIC_CONFIG}',
           fromEnvVar: '${DYNAMIC_ENVVAR}',
-        }
+        },
       );
 
       // result should get value from config.json
@@ -821,8 +820,8 @@ describe('executor', function() {
     });
 
     it('`env-var` should have precedence over `config`', function(done) {
-      var key = 'DYNAMIC_VARIABLE';
-      var bootInstructions = simpleComponentConfig({
+      const key = 'DYNAMIC_VARIABLE';
+      const bootInstructions = simpleComponentConfig({
         path: '${restApiRoot}',
         isDynamic: '${' + key + '}',
       });
@@ -841,7 +840,7 @@ describe('executor', function() {
 
     it('should parse multiple config variables', function(done) {
       boot.execute(app, simpleComponentConfig(
-        {path: '${restApiRoot}', env: '${env}'}
+        {path: '${restApiRoot}', env: '${env}'},
       ), function(err) {
         if (err) return done(err);
 
@@ -856,14 +855,14 @@ describe('executor', function() {
 
     it('should parse config variables in an array', function(done) {
       boot.execute(app, simpleComponentConfig(
-        {paths: ['${restApiRoot}']}
+        {paths: ['${restApiRoot}']},
       ), function(err) {
         if (err) return done(err);
 
         supertest(app).get('/component').end(function(err, res) {
           if (err) return done(err);
           expect(res.body.paths).to.eql(
-            [app.get('restApiRoot')]
+            [app.get('restApiRoot')],
           );
           done();
         });
@@ -872,7 +871,7 @@ describe('executor', function() {
 
     it('should parse config variables in an object', function(done) {
       boot.execute(app, simpleComponentConfig(
-        {info: {path: '${restApiRoot}'}}
+        {info: {path: '${restApiRoot}'}},
       ), function(err) {
         if (err) return done(err);
 
@@ -888,7 +887,7 @@ describe('executor', function() {
 
     it('should parse config variables in a nested object', function(done) {
       boot.execute(app, simpleComponentConfig(
-        {nested: {info: {path: '${restApiRoot}'}}}
+        {nested: {info: {path: '${restApiRoot}'}}},
       ), function(err) {
         if (err) return done(err);
 
@@ -904,7 +903,7 @@ describe('executor', function() {
   });
 
   it('calls function exported by boot/init.js', function(done) {
-    var file = appdir.writeFileSync('boot/init.js',
+    const file = appdir.writeFileSync('boot/init.js',
       'module.exports = function(app) { app.fnCalled = true; };');
 
     delete app.fnCalled;
@@ -917,7 +916,7 @@ describe('executor', function() {
   });
 
   it('configures middleware', function(done) {
-    var pushNamePath = require.resolve('./helpers/push-name-middleware');
+    const pushNamePath = require.resolve('./helpers/push-name-middleware');
 
     boot.execute(app, someInstructions({
       middleware: {
@@ -961,7 +960,7 @@ describe('executor', function() {
         .get('/')
         .end(function(err, res) {
           if (err) return done(err);
-          var names = (res.headers.names || '').split(',');
+          const names = (res.headers.names || '').split(',');
           expect(names).to.eql(['initial', 'custom', 'routes']);
           done();
         });
@@ -989,7 +988,7 @@ describe('executor', function() {
         .get('/')
         .end(function(err, res) {
           if (err) return done(err);
-          var EXPECTED_TEXT = '<!DOCTYPE html>\n<html>\n<head lang="en">\n' +
+          const EXPECTED_TEXT = '<!DOCTYPE html>\n<html>\n<head lang="en">\n' +
             '    <meta charset="UTF-8">\n    <title>simple-app</title>\n' +
             '</head>\n<body>\n<h1>simple-app</h1>\n' +
             '</body>\n</html>';
@@ -1031,7 +1030,7 @@ describe('executor', function() {
       if (err) return done(err);
 
       expect(Object.keys(require.cache)).to.include(
-        appdir.resolve('components/test-component/index.js')
+        appdir.resolve('components/test-component/index.js'),
       );
 
       expect(app.componentOptions).to.eql({option: 'value'});
@@ -1052,7 +1051,7 @@ describe('executor', function() {
       if (err) return done(err);
 
       expect(Object.keys(require.cache)).to.not.include(
-        appdir.resolve('components/test-component/index.js')
+        appdir.resolve('components/test-component/index.js'),
       );
       done();
     });
@@ -1075,14 +1074,14 @@ describe('executor', function() {
         if (err) return done(err);
 
         expect(Object.keys(require.cache)).to.not.include(
-          appdir.resolve('components/test-component/index.js')
+          appdir.resolve('components/test-component/index.js'),
         );
         done();
       });
     });
 
   it('configures middleware (that requires `this`)', function(done) {
-    var passportPath = require.resolve('./fixtures/passport');
+    const passportPath = require.resolve('./fixtures/passport');
 
     boot.execute(app, someInstructions({
       middleware: {
@@ -1122,7 +1121,7 @@ describe('executor', function() {
   });
 
   describe('when booting with lazy connect', function() {
-    var SAMPLE_INSTRUCTION = someInstructions({
+    const SAMPLE_INSTRUCTION = someInstructions({
       dataSources: {
         lazyConnector: {
           connector: 'testLazyConnect',
@@ -1130,7 +1129,7 @@ describe('executor', function() {
         },
       },
     });
-    var connectTriggered = true;
+    let connectTriggered = true;
 
     beforeEach(function() {
       app.connector('testLazyConnect', {
@@ -1184,14 +1183,14 @@ describe('executor', function() {
     });
 
     it('should convert dynamic variable for datasource', function(done) {
-      var datasource = {
+      const datasource = {
         mydb: {
           connector: 'memory',
           host: '${DYNAMIC_HOST}',
           port: '${DYNAMIC_PORT}',
         },
       };
-      var bootInstructions = {dataSources: datasource};
+      const bootInstructions = {dataSources: datasource};
 
       process.env.DYNAMIC_PORT = '10007';
       process.env.DYNAMIC_HOST = '123.321.123.132';
@@ -1204,20 +1203,20 @@ describe('executor', function() {
     });
 
     it('should resolve dynamic config via app.get()', function(done) {
-      var datasource = {
+      const datasource = {
         mydb: {
           connector: 'memory',
           host: '${DYNAMIC_HOST}',
         },
       };
-      var bootInstructions = {
+      const bootInstructions = {
         application: {DYNAMIC_HOST: '127.0.0.4'},
         dataSources: datasource,
       };
       boot.execute(app, someInstructions(bootInstructions), function() {
         expect(app.get('DYNAMIC_HOST')).to.equal('127.0.0.4');
         expect(app.datasources.mydb.settings.host).to.equal(
-          '127.0.0.4'
+          '127.0.0.4',
         );
         done();
       });
@@ -1225,13 +1224,13 @@ describe('executor', function() {
 
     it('should take ENV precedence over config.json', function(done) {
       process.env.DYNAMIC_HOST = '127.0.0.2';
-      var datasource = {
+      const datasource = {
         mydb: {
           connector: 'memory',
           host: '${DYNAMIC_HOST}',
         },
       };
-      var bootInstructions = {
+      const bootInstructions = {
         application: {DYNAMIC_HOST: '127.0.0.3'},
         dataSources: datasource,
       };
@@ -1243,13 +1242,13 @@ describe('executor', function() {
     });
 
     it('empty dynamic conf should resolve as `undefined`', function(done) {
-      var datasource = {
+      const datasource = {
         mydb: {
           connector: 'memory',
           host: '${DYNAMIC_HOST}',
         },
       };
-      var bootInstructions = {dataSources: datasource};
+      const bootInstructions = {dataSources: datasource};
 
       boot.execute(app, someInstructions(bootInstructions), function() {
         expect(app.get('DYNAMIC_HOST')).to.be.undefined();
@@ -1266,7 +1265,7 @@ function simpleMiddlewareConfig(phase, paths, params) {
     paths = undefined;
   }
 
-  var config = {
+  const config = {
     phase: phase,
     params: params,
   };
@@ -1315,7 +1314,7 @@ assert.isFunc = function(obj, name) {
 };
 
 function someInstructions(values) {
-  var result = {
+  const result = {
     application: values.application || {},
     models: values.models || [],
     dataSources: values.dataSources || {db: {connector: 'memory'}},
@@ -1328,7 +1327,7 @@ function someInstructions(values) {
     result.env = values.env;
 
   if (values.files) {
-    for (var k in values.files)
+    for (const k in values.files)
       result.files[k] = values.files[k];
   }
 
diff --git a/test/fixtures/browser-app-2/app.js b/test/fixtures/browser-app-2/app.js
index 5b9141b..d333560 100644
--- a/test/fixtures/browser-app-2/app.js
+++ b/test/fixtures/browser-app-2/app.js
@@ -5,10 +5,10 @@
 
 'use strict';
 
-var loopback = require('loopback');
-var boot = require('../../../');
+const loopback = require('loopback');
+const boot = require('../../../');
 
-var app = module.exports = loopback();
+const app = module.exports = loopback();
 boot(app, {
   appId: 'browserApp2',
   appRootDir: __dirname,
diff --git a/test/fixtures/browser-app/app.js b/test/fixtures/browser-app/app.js
index 6f853b1..478b6cf 100644
--- a/test/fixtures/browser-app/app.js
+++ b/test/fixtures/browser-app/app.js
@@ -5,8 +5,8 @@
 
 'use strict';
 
-var loopback = require('loopback');
-var boot = require('../../../');
+const loopback = require('loopback');
+const boot = require('../../../');
 
-var app = module.exports = loopback();
+const app = module.exports = loopback();
 boot(app, __dirname);
diff --git a/test/fixtures/passport.js b/test/fixtures/passport.js
index d4ca24e..34adabb 100644
--- a/test/fixtures/passport.js
+++ b/test/fixtures/passport.js
@@ -5,7 +5,7 @@
 
 'use strict';
 
-var framework = {
+const framework = {
   initialize: function(passport) {
     return function(req, res, next) {
       req._passport = passport;
@@ -15,7 +15,7 @@ var framework = {
   },
 };
 
-var Passport = function() {
+const Passport = function() {
   this._framework = framework;
 };
 
diff --git a/test/fixtures/simple-app/boot/promise-callback.js b/test/fixtures/simple-app/boot/promise-callback.js
index 1fb7e80..55ef4d2 100644
--- a/test/fixtures/simple-app/boot/promise-callback.js
+++ b/test/fixtures/simple-app/boot/promise-callback.js
@@ -5,7 +5,7 @@
 
 'use strict';
 
-var Promise = require('bluebird');
+const Promise = require('bluebird');
 
 module.exports = function(app, callback) {
   callback();
diff --git a/test/fixtures/simple-app/boot/promise.js b/test/fixtures/simple-app/boot/promise.js
index 38c3825..81258f1 100644
--- a/test/fixtures/simple-app/boot/promise.js
+++ b/test/fixtures/simple-app/boot/promise.js
@@ -5,7 +5,7 @@
 
 'use strict';
 
-var Promise = require('bluebird');
+const Promise = require('bluebird');
 
 process.bootFlags.push('promiseLoaded');
 module.exports = function(app) {
diff --git a/test/fixtures/simple-app/boot/reject.js b/test/fixtures/simple-app/boot/reject.js
index 7978cc4..35d37c9 100644
--- a/test/fixtures/simple-app/boot/reject.js
+++ b/test/fixtures/simple-app/boot/reject.js
@@ -5,7 +5,7 @@
 
 'use strict';
 
-var Promise = require('bluebird');
+const Promise = require('bluebird');
 
 module.exports = function(app) {
   if (process.rejectPromise) {
diff --git a/test/helpers/appdir.js b/test/helpers/appdir.js
index aca3b3b..53e6350 100644
--- a/test/helpers/appdir.js
+++ b/test/helpers/appdir.js
@@ -5,14 +5,14 @@
 
 'use strict';
 
-var path = require('path');
-var fs = require('fs-extra');
-var extend = require('util')._extend;
-var sandbox = require('./sandbox');
+const path = require('path');
+const fs = require('fs-extra');
+const extend = require('util')._extend;
+const sandbox = require('./sandbox');
 
-var appdir = exports;
+const appdir = exports;
 
-var PATH = appdir.PATH = null;
+let PATH = appdir.PATH = null;
 
 appdir.init = function(cb) {
   // Node's module loader has a very aggressive caching, therefore
@@ -20,7 +20,7 @@ appdir.init = function(cb) {
   // The code here is used to generate a random string
   require('crypto').randomBytes(5, function(err, buf) {
     if (err) return cb(err);
-    var randomStr = buf.toString('hex');
+    const randomStr = buf.toString('hex');
     PATH = appdir.PATH = sandbox.resolve(randomStr);
     cb(null, appdir.PATH);
   });
@@ -49,7 +49,7 @@ appdir.writeConfigFileSync = function(name, json) {
 };
 
 appdir.writeFileSync = function(name, content) {
-  var filePath = this.resolve(name);
+  const filePath = this.resolve(name);
   fs.mkdirsSync(path.dirname(filePath));
   fs.writeFileSync(filePath, content, 'utf-8');
   return filePath;
diff --git a/test/helpers/browser.js b/test/helpers/browser.js
index 8680bc5..f01546f 100644
--- a/test/helpers/browser.js
+++ b/test/helpers/browser.js
@@ -5,10 +5,10 @@
 
 'use strict';
 
-var vm = require('vm');
+const vm = require('vm');
 
 function createContext() {
-  var context = {
+  const context = {
     // required by browserify
     XMLHttpRequest: function() {},
     clearTimeout: function() {},
@@ -33,7 +33,7 @@ function createContext() {
     DataView: DataView,
     crypto: {
       getRandomValues: function(typedArray) {
-        var randomBuffer = require('crypto').randomBytes(typedArray.length);
+        const randomBuffer = require('crypto').randomBytes(typedArray.length);
         // This implementation is not secure: we take random 8bit values
         // and assign them to 8/16/32bit values, leaving high-order bits
         // filled with zeroes.
@@ -73,9 +73,9 @@ function createContext() {
 exports.createContext = createContext;
 
 function printContextLogs(context) {
-  var k, ix; // see https://github.com/eslint/eslint/issues/5744
+  let k, ix; // see https://github.com/eslint/eslint/issues/5744
   for (k in context.console._logs) {
-    var items = context.console._logs[k];
+    const items = context.console._logs[k];
     for (ix in items) {
       console[k].apply(console, items[ix]);
     }
diff --git a/test/helpers/browserify.js b/test/helpers/browserify.js
index ea332fe..bb28b95 100644
--- a/test/helpers/browserify.js
+++ b/test/helpers/browserify.js
@@ -5,12 +5,12 @@
 
 'use strict';
 
-var fs = require('fs');
-var sandbox = require('./sandbox');
+const fs = require('fs');
+const sandbox = require('./sandbox');
 
 function exportToSandbox(b, fileName, callback) {
-  var bundlePath = sandbox.resolve(fileName);
-  var out = fs.createWriteStream(bundlePath);
+  const bundlePath = sandbox.resolve(fileName);
+  const out = fs.createWriteStream(bundlePath);
   b.bundle().pipe(out);
 
   out.on('error', function(err) {
diff --git a/test/helpers/sandbox.js b/test/helpers/sandbox.js
index 7c07737..dd5afe7 100644
--- a/test/helpers/sandbox.js
+++ b/test/helpers/sandbox.js
@@ -5,10 +5,10 @@
 
 'use strict';
 
-var fs = require('fs-extra');
-var path = require('path');
+const fs = require('fs-extra');
+const path = require('path');
 
-var sandbox = exports;
+const sandbox = exports;
 sandbox.PATH = path.join(__dirname, '..', 'sandbox');
 
 sandbox.reset = function() {
@@ -17,7 +17,7 @@ sandbox.reset = function() {
 };
 
 sandbox.resolve = function() {
-  var args = Array.prototype.slice.apply(arguments);
+  const args = Array.prototype.slice.apply(arguments);
   args.unshift(sandbox.PATH);
   return path.resolve.apply(path.resolve, args);
 };
diff --git a/test/utils.test.js b/test/utils.test.js
index 1a60dcf..ee69a2b 100644
--- a/test/utils.test.js
+++ b/test/utils.test.js
@@ -5,10 +5,10 @@
 
 'use strict';
 
-var utils = require('../lib/utils');
-var expect = require('chai').expect;
-var sandbox = require('./helpers/sandbox');
-var appdir = require('./helpers/appdir');
+const utils = require('../lib/utils');
+const expect = require('chai').expect;
+const sandbox = require('./helpers/sandbox');
+const appdir = require('./helpers/appdir');
 
 describe('utils', function() {
   beforeEach(sandbox.reset);
@@ -17,13 +17,13 @@ describe('utils', function() {
   });
   describe('fileExistsSync', function() {
     it('returns false when a file does not exist', function() {
-      var doesNotExist = sandbox.resolve('does-not-exist.json');
+      const doesNotExist = sandbox.resolve('does-not-exist.json');
       expect(utils.fileExistsSync(doesNotExist))
         .to.equal(false);
     });
 
     it('returns true when a file does exist', function() {
-      var doesExist = appdir.writeConfigFileSync('does-exist.json', {
+      const doesExist = appdir.writeConfigFileSync('does-exist.json', {
         exists: true,
       });
       expect(utils.fileExistsSync(doesExist))