server-app: middleware API improvements

- Rename `config.config` to `config.params`
 - Modify methods to return `this` (fluent API)

lib/server-app.js

@@ -22,7 +22,7 @@ module.exports = function loopbackExpress() {
  * app.middlewareFromConfig(compression, {
  *   enabled: true,
  *   phase: 'initial',
- *   config: {
+ *   params: {
  *     threshold: 128
  *   }
  * });
@@ -33,6 +33,8 @@ module.exports = function loopbackExpress() {
  * @param {Array|*} config The configuration. Either an array of arguments
  *   to pass to the factory function, or the value of the first argument
  *   when the factory expects a single argument only.
+ *
+ * @returns {object} this (fluent API)
  */
 proto.middlewareFromConfig = function(factory, config) {
   assert(typeof factory === 'function', '"factory" must be a function');
@@ -43,15 +45,17 @@ proto.middlewareFromConfig = function(factory, config) {
   if (config.enabled === false)
     return;
 
-  var args = config.config;
-  if (args === undefined) {
-    args = [];
-  } else if (!Array.isArray(args)) {
-    args = [args];
+  var params = config.params;
+  if (params === undefined) {
+    params = [];
+  } else if (!Array.isArray(params)) {
+    params = [params];
   }
 
-  var handler = factory.apply(null, args);
+  var handler = factory.apply(null, params);
   this.middleware(config.phase, handler);
+
+  return this;
 };
 
 /**
@@ -81,6 +85,8 @@ proto.middlewareFromConfig = function(factory, config) {
  *
  * @param {string|Array.<string>} nameOrArray A phase name or a list of phase
  *   names to add.
+ *
+ * @returns {object} this (fluent API)
  */
 proto.defineMiddlewarePhases = function(nameOrArray) {
   this.lazyrouter();
@@ -90,6 +96,8 @@ proto.defineMiddlewarePhases = function(nameOrArray) {
   } else {
     this._requestHandlingPhases.addBefore('routes', nameOrArray);
   }
+
+  return this;
 };
 
 /**

test/app.test.js

@@ -110,28 +110,28 @@ describe('app', function() {
       app.middlewareFromConfig(handlerFactory, {
         enabled: true,
         phase: 'session',
-        config: expectedConfig
+        params: expectedConfig
       });
 
       // Config as a value (single arg)
       app.middlewareFromConfig(handlerFactory, {
         enabled: true,
         phase: 'session:before',
-        config: 'before'
+        params: 'before'
       });
 
       // Config as a list of args
       app.middlewareFromConfig(handlerFactory, {
         enabled: true,
         phase: 'session:after',
-        config: ['after', 2]
+        params: ['after', 2]
       });
 
       // Disabled by configuration
       app.middlewareFromConfig(handlerFactory, {
         enabled: false,
         phase: 'initial',
-        config: null
+        params: null
       });
 
       executeMiddlewareHandlers(app, function(err) {