diff --git a/lib/clone.js b/lib/clone.js
index 6f39535..60391a5 100644
--- a/lib/clone.js
+++ b/lib/clone.js
@@ -1,3 +1,4 @@
+'use strict';
 module.exports = cloneAllProperties;
 
 /**
diff --git a/lib/content-negotiation.js b/lib/content-negotiation.js
index 6222025..5605f9a 100644
--- a/lib/content-negotiation.js
+++ b/lib/content-negotiation.js
@@ -3,6 +3,7 @@
 // This file is licensed under the MIT License.
 // License text available at https://opensource.org/licenses/MIT
 
+'use strict';
 var accepts = require('accepts');
 var debug = require('debug')('strong-error-handler:http-response');
 var sendJson = require('./send-json');
diff --git a/lib/send-html.js b/lib/send-html.js
index 4b00ca0..5bcd938 100644
--- a/lib/send-html.js
+++ b/lib/send-html.js
@@ -3,6 +3,7 @@
 // This file is licensed under the MIT License.
 // License text available at https://opensource.org/licenses/MIT
 
+'use strict';
 var ejs = require('ejs');
 var fs = require('fs');
 var path = require('path');
@@ -30,7 +31,7 @@ function sendHtml(res, data, options) {
  */
 function compileTemplate(filepath) {
   var options = {cache: true, filename: filepath};
-  fileContent = fs.readFileSync(filepath, 'utf8');
+  var fileContent = fs.readFileSync(filepath, 'utf8');
   return ejs.compile(fileContent, options);
 }
 
diff --git a/package.json b/package.json
index 28921ca..fcc49f8 100644
--- a/package.json
+++ b/package.json
@@ -21,8 +21,8 @@
   },
   "devDependencies": {
     "chai": "^2.1.1",
-    "eslint": "^2.5.3",
-    "eslint-config-loopback": "^3.0.0",
+    "eslint": "^2.13.1",
+    "eslint-config-loopback": "^4.0.0",
     "express": "^4.13.4",
     "mocha": "^2.1.0",
     "supertest": "^1.1.0"