diff --git a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/JavascriptClientCodegen.java b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/JavascriptClientCodegen.java
index 0b56ffbbe81..c95bec5e347 100644
--- a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/JavascriptClientCodegen.java
+++ b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/JavascriptClientCodegen.java
@@ -7,6 +7,7 @@
 import io.swagger.codegen.CodegenConstants;
 import io.swagger.codegen.CodegenModel;
 import io.swagger.codegen.CodegenOperation;
+import io.swagger.codegen.CodegenParameter;
 import io.swagger.codegen.CodegenProperty;
 import io.swagger.codegen.CodegenType;
 import io.swagger.codegen.SupportingFile;
@@ -445,6 +446,35 @@ public CodegenModel fromModel(String name, Model model, Map<String, Model> allDe
         return codegenModel;
     }
 
+    @Override
+    public Map<String, Object> postProcessOperations(Map<String, Object> objs) {
+        // Generate and store argument list string of each operation into
+        // vendor-extension: x-codegen-argList.
+        Map<String, Object> operations = (Map<String, Object>) objs.get("operations");
+        if (operations != null) {
+            List<CodegenOperation> ops = (List<CodegenOperation>) operations.get("operation");
+            for (CodegenOperation operation : ops) {
+                List<String> argList = new ArrayList();
+                boolean hasOptionalParams = false;
+                for (CodegenParameter p : operation.allParams) {
+                    if (p.required != null && p.required) {
+                        argList.add(p.paramName);
+                    } else {
+                      hasOptionalParams = true;
+                    }
+                }
+                if (hasOptionalParams) {
+                    argList.add("opts");
+                }
+                if (!usePromises) {
+                    argList.add("callback");
+                }
+                operation.vendorExtensions.put("x-codegen-argList", StringUtils.join(argList, ", "));
+            }
+        }
+        return objs;
+    }
+
     @Override
     public Map<String, Object> postProcessModels(Map<String, Object> objs) {
         List<Object> models = (List<Object>) objs.get("models");
@@ -488,7 +518,7 @@ public Map<String, Object> postProcessModels(Map<String, Object> objs) {
                 }
                 allowableValues.put("enumVars", enumVars);
             }
-            // set vendor-extension: x-hasMoreRequired
+            // set vendor-extension: x-codegen-hasMoreRequired
             CodegenProperty lastRequired = null;
             for (CodegenProperty var : cm.vars) {
                 if (var.required != null && var.required) {
@@ -497,9 +527,9 @@ public Map<String, Object> postProcessModels(Map<String, Object> objs) {
             }
             for (CodegenProperty var : cm.vars) {
                 if (var == lastRequired) {
-                    var.vendorExtensions.put("x-hasMoreRequired", false);
+                    var.vendorExtensions.put("x-codegen-hasMoreRequired", false);
                 } else if (var.required != null && var.required) {
-                    var.vendorExtensions.put("x-hasMoreRequired", true);
+                    var.vendorExtensions.put("x-codegen-hasMoreRequired", true);
                 }
             }
         }
diff --git a/modules/swagger-codegen/src/main/resources/Javascript/api.mustache b/modules/swagger-codegen/src/main/resources/Javascript/api.mustache
index a42ad349820..79a5fd2a674 100644
--- a/modules/swagger-codegen/src/main/resources/Javascript/api.mustache
+++ b/modules/swagger-codegen/src/main/resources/Javascript/api.mustache
@@ -1,54 +1,54 @@
-(function(root, factory) {
+{{=< >=}}(function(root, factory) {
   if (typeof define === 'function' && define.amd) {
     // AMD. Register as an anonymous module.
-    define(['../ApiClient'{{#imports}}, '../model/{{import}}'{{/imports}}], factory);
+    define(['../ApiClient'<#imports>, '../model/<import>'</imports>], factory);
   } else if (typeof module === 'object' && module.exports) {
     // CommonJS-like environments that support module.exports, like Node.
-    module.exports = factory(require('../ApiClient'){{#imports}}, require('../model/{{import}}'){{/imports}});
+    module.exports = factory(require('../ApiClient')<#imports>, require('../model/<import>')</imports>);
   } else {
     // Browser globals (root is window)
-    if (!root.{{moduleName}}) {
-      root.{{moduleName}} = {};
+    if (!root.<moduleName>) {
+      root.<moduleName> = {};
     }
-    root.{{moduleName}}.{{classname}} = factory(root.{{moduleName}}.ApiClient{{#imports}}, root.{{moduleName}}.{{import}}{{/imports}});
+    root.<moduleName>.<classname> = factory(root.<moduleName>.ApiClient<#imports>, root.<moduleName>.<import></imports>);
   }
-}(this, function(ApiClient{{#imports}}, {{import}}{{/imports}}) {
+}(this, function(ApiClient<#imports>, <import></imports>) {
   'use strict';
 
-  var {{classname}} = function {{classname}}(apiClient) {
+  var <classname> = function <classname>(apiClient) {
     this.apiClient = apiClient || ApiClient.default;
 
     var self = this;
-    {{#operations}}
-    {{#operation}}
+    <#operations>
+    <#operation>
     /**
-     * {{summary}}
-     * {{notes}}
-  {{#allParams}}   * @param {{=<% %>=}}{<% dataType %>} <%={{ }}=%> {{paramName}} {{description}}
-  {{/allParams}}   {{^usePromises}}* @param {function} callback the callback function, accepting three arguments: error, data, response{{/usePromises}}{{#returnType}}
-     *   data is of type: {{{returnType}}}{{/returnType}}
+     * <summary>
+     * <notes><#allParams>
+     * @param {<dataType>} <#required><paramName></required><^required>opts['<paramName>']</required> <description></allParams><^usePromises>
+     * @param {function} callback the callback function, accepting three arguments: error, data, response</usePromises><#returnType>
+     *   data is of type: <&returnType></returnType>
      */
-    self.{{nickname}} = function({{#allParams}}{{paramName}}{{#hasMore}}, {{/hasMore}}{{/allParams}}{{^usePromises}}{{#hasParams}}, {{/hasParams}}callback{{/usePromises}}) {
-      var postBody = {{#bodyParam}}{{paramName}}{{/bodyParam}}{{^bodyParam}}null{{/bodyParam}};
-      {{#allParams}}{{#required}}
-      // verify the required parameter '{{paramName}}' is set
-      if ({{paramName}} == null) {
-        throw "Missing the required parameter '{{paramName}}' when calling {{nickname}}";
+    self.<nickname> = function(<vendorExtensions.x-codegen-argList>) {<#hasOptionalParams>
+      opts = opts || {};</hasOptionalParams>
+      var postBody = <#bodyParam><#required><paramName></required><^required>opts['<paramName>']</required></bodyParam><^bodyParam>null</bodyParam>;
+      <#allParams><#required>
+      // verify the required parameter '<paramName>' is set
+      if (<paramName> == null) {
+        throw "Missing the required parameter '<paramName>' when calling <nickname>";
       }
-      {{/required}}{{/allParams}}
+      </required></allParams>
 
-      {{=< >=}}
       var pathParams = {<#pathParams>
-        '<baseName>': <paramName><#hasMore>,</hasMore></pathParams>
+        '<baseName>': <#required><paramName></required><^required>opts['<paramName>']</required><#hasMore>,</hasMore></pathParams>
       };
       var queryParams = {<#queryParams>
-        '<baseName>': <#collectionFormat>this.apiClient.buildCollectionParam(<paramName>, '<collectionFormat>')</collectionFormat><^collectionFormat><paramName></collectionFormat><#hasMore>,</hasMore></queryParams>
+        '<baseName>': <#collectionFormat>this.apiClient.buildCollectionParam(<#required><paramName></required><^required>opts['<paramName>']</required>, '<collectionFormat>')</collectionFormat><^collectionFormat><#required><paramName></required><^required>opts['<paramName>']</required></collectionFormat><#hasMore>,</hasMore></queryParams>
       };
       var headerParams = {<#headerParams>
-        '<baseName>': <paramName><#hasMore>,</hasMore></headerParams>
+        '<baseName>': <#required><paramName></required><^required>opts['<paramName>']</required><#hasMore>,</hasMore></headerParams>
       };
       var formParams = {<#formParams>
-        '<baseName>': <#collectionFormat>this.apiClient.buildCollectionParam(<paramName>, '<collectionFormat>')</collectionFormat><^collectionFormat><paramName></collectionFormat><#hasMore>,</hasMore></formParams>
+        '<baseName>': <#collectionFormat>this.apiClient.buildCollectionParam(<#required><paramName></required><^required>opts['<paramName>']</required>, '<collectionFormat>')</collectionFormat><^collectionFormat><#required><paramName></required><^required>opts['<paramName>']</required></collectionFormat><#hasMore>,</hasMore></formParams>
       };
 
       var authNames = [<#authMethods>'<name>'<#hasMore>, </hasMore></authMethods>];
@@ -61,11 +61,11 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType<^usePromises>, callback</usePromises>
       );
-      <={{ }}=>
+
     }
-    {{/operation}}
-    {{/operations}}
+    </operation>
+    </operations>
   };
 
-  return {{classname}};
-}));
+  return <classname>;
+}));<={{ }}=>
diff --git a/modules/swagger-codegen/src/main/resources/Javascript/model.mustache b/modules/swagger-codegen/src/main/resources/Javascript/model.mustache
index 9420afde771..1f0f48226a7 100644
--- a/modules/swagger-codegen/src/main/resources/Javascript/model.mustache
+++ b/modules/swagger-codegen/src/main/resources/Javascript/model.mustache
@@ -18,7 +18,7 @@
   {{#description}}/**
    * {{description}}
    **/{{/description}}
-  var {{classname}} = function {{classname}}({{#vars}}{{#required}}{{name}}{{#vendorExtensions.x-hasMoreRequired}}, {{/vendorExtensions.x-hasMoreRequired}}{{/required}}{{/vars}}) { {{#parent}}/* extends {{{parent}}}*/{{/parent}}
+  var {{classname}} = function {{classname}}({{#vars}}{{#required}}{{name}}{{#vendorExtensions.x-codegen-hasMoreRequired}}, {{/vendorExtensions.x-codegen-hasMoreRequired}}{{/required}}{{/vars}}) { {{#parent}}/* extends {{{parent}}}*/{{/parent}}
     {{#vars}}{{#required}}
     /**{{#description}}
      * {{{description}}}{{/description}}
diff --git a/samples/client/petstore/javascript-promise/src/api/PetApi.js b/samples/client/petstore/javascript-promise/src/api/PetApi.js
index 26e0e633ad6..b9dd09d6d9f 100644
--- a/samples/client/petstore/javascript-promise/src/api/PetApi.js
+++ b/samples/client/petstore/javascript-promise/src/api/PetApi.js
@@ -24,14 +24,13 @@
     /**
      * Update an existing pet
      * 
-     * @param {Pet}  body Pet object that needs to be added to the store
-     
+     * @param {Pet} opts['body'] Pet object that needs to be added to the store
      */
-    self.updatePet = function(body) {
-      var postBody = body;
+    self.updatePet = function(opts) {
+      opts = opts || {};
+      var postBody = opts['body'];
       
 
-      
       var pathParams = {
       };
       var queryParams = {
@@ -51,20 +50,19 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType
       );
-      
+
     }
     
     /**
      * Add a new pet to the store
      * 
-     * @param {Pet}  body Pet object that needs to be added to the store
-     
+     * @param {Pet} opts['body'] Pet object that needs to be added to the store
      */
-    self.addPet = function(body) {
-      var postBody = body;
+    self.addPet = function(opts) {
+      opts = opts || {};
+      var postBody = opts['body'];
       
 
-      
       var pathParams = {
       };
       var queryParams = {
@@ -84,25 +82,24 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType
       );
-      
+
     }
     
     /**
      * Finds Pets by status
      * Multiple status values can be provided with comma seperated strings
-     * @param {[String]}  status Status values that need to be considered for filter
-     
+     * @param {[String]} opts['status'] Status values that need to be considered for filter
      *   data is of type: [Pet]
      */
-    self.findPetsByStatus = function(status) {
+    self.findPetsByStatus = function(opts) {
+      opts = opts || {};
       var postBody = null;
       
 
-      
       var pathParams = {
       };
       var queryParams = {
-        'status': this.apiClient.buildCollectionParam(status, 'multi')
+        'status': this.apiClient.buildCollectionParam(opts['status'], 'multi')
       };
       var headerParams = {
       };
@@ -119,25 +116,24 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType
       );
-      
+
     }
     
     /**
      * Finds Pets by tags
      * Muliple tags can be provided with comma seperated strings. Use tag1, tag2, tag3 for testing.
-     * @param {[String]}  tags Tags to filter by
-     
+     * @param {[String]} opts['tags'] Tags to filter by
      *   data is of type: [Pet]
      */
-    self.findPetsByTags = function(tags) {
+    self.findPetsByTags = function(opts) {
+      opts = opts || {};
       var postBody = null;
       
 
-      
       var pathParams = {
       };
       var queryParams = {
-        'tags': this.apiClient.buildCollectionParam(tags, 'multi')
+        'tags': this.apiClient.buildCollectionParam(opts['tags'], 'multi')
       };
       var headerParams = {
       };
@@ -154,14 +150,13 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType
       );
-      
+
     }
     
     /**
      * Find pet by ID
      * Returns a pet when ID &lt; 10.  ID &gt; 10 or nonintegers will simulate API error conditions
-     * @param {Integer}  petId ID of pet that needs to be fetched
-     
+     * @param {Integer} petId ID of pet that needs to be fetched
      *   data is of type: Pet
      */
     self.getPetById = function(petId) {
@@ -173,7 +168,6 @@
       }
       
 
-      
       var pathParams = {
         'petId': petId
       };
@@ -194,18 +188,18 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType
       );
-      
+
     }
     
     /**
      * Updates a pet in the store with form data
      * 
-     * @param {String}  petId ID of pet that needs to be updated
-     * @param {String}  name Updated name of the pet
-     * @param {String}  status Updated status of the pet
-     
+     * @param {String} petId ID of pet that needs to be updated
+     * @param {String} opts['name'] Updated name of the pet
+     * @param {String} opts['status'] Updated status of the pet
      */
-    self.updatePetWithForm = function(petId, name, status) {
+    self.updatePetWithForm = function(petId, opts) {
+      opts = opts || {};
       var postBody = null;
       
       // verify the required parameter 'petId' is set
@@ -214,7 +208,6 @@
       }
       
 
-      
       var pathParams = {
         'petId': petId
       };
@@ -223,8 +216,8 @@
       var headerParams = {
       };
       var formParams = {
-        'name': name,
-        'status': status
+        'name': opts['name'],
+        'status': opts['status']
       };
 
       var authNames = ['petstore_auth'];
@@ -237,17 +230,17 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType
       );
-      
+
     }
     
     /**
      * Deletes a pet
      * 
-     * @param {Integer}  petId Pet id to delete
-     * @param {String}  apiKey 
-     
+     * @param {Integer} petId Pet id to delete
+     * @param {String} opts['apiKey'] 
      */
-    self.deletePet = function(petId, apiKey) {
+    self.deletePet = function(petId, opts) {
+      opts = opts || {};
       var postBody = null;
       
       // verify the required parameter 'petId' is set
@@ -256,14 +249,13 @@
       }
       
 
-      
       var pathParams = {
         'petId': petId
       };
       var queryParams = {
       };
       var headerParams = {
-        'api_key': apiKey
+        'api_key': opts['apiKey']
       };
       var formParams = {
       };
@@ -278,18 +270,18 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType
       );
-      
+
     }
     
     /**
      * uploads an image
      * 
-     * @param {Integer}  petId ID of pet to update
-     * @param {String}  additionalMetadata Additional data to pass to server
-     * @param {File}  file file to upload
-     
+     * @param {Integer} petId ID of pet to update
+     * @param {String} opts['additionalMetadata'] Additional data to pass to server
+     * @param {File} opts['file'] file to upload
      */
-    self.uploadFile = function(petId, additionalMetadata, file) {
+    self.uploadFile = function(petId, opts) {
+      opts = opts || {};
       var postBody = null;
       
       // verify the required parameter 'petId' is set
@@ -298,7 +290,6 @@
       }
       
 
-      
       var pathParams = {
         'petId': petId
       };
@@ -307,8 +298,8 @@
       var headerParams = {
       };
       var formParams = {
-        'additionalMetadata': additionalMetadata,
-        'file': file
+        'additionalMetadata': opts['additionalMetadata'],
+        'file': opts['file']
       };
 
       var authNames = ['petstore_auth'];
@@ -321,14 +312,13 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType
       );
-      
+
     }
     
     /**
      * Fake endpoint to test byte array return by &#39;Find pet by ID&#39;
      * Returns a pet when ID &lt; 10.  ID &gt; 10 or nonintegers will simulate API error conditions
-     * @param {Integer}  petId ID of pet that needs to be fetched
-     
+     * @param {Integer} petId ID of pet that needs to be fetched
      *   data is of type: 'String'
      */
     self.getPetByIdWithByteArray = function(petId) {
@@ -340,7 +330,6 @@
       }
       
 
-      
       var pathParams = {
         'petId': petId
       };
@@ -361,20 +350,19 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType
       );
-      
+
     }
     
     /**
      * Fake endpoint to test byte array in body parameter for adding a new pet to the store
      * 
-     * @param {String}  body Pet object in the form of byte array
-     
+     * @param {String} opts['body'] Pet object in the form of byte array
      */
-    self.addPetUsingByteArray = function(body) {
-      var postBody = body;
+    self.addPetUsingByteArray = function(opts) {
+      opts = opts || {};
+      var postBody = opts['body'];
       
 
-      
       var pathParams = {
       };
       var queryParams = {
@@ -394,7 +382,7 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType
       );
-      
+
     }
     
     
diff --git a/samples/client/petstore/javascript-promise/src/api/StoreApi.js b/samples/client/petstore/javascript-promise/src/api/StoreApi.js
index 57a3c57d86f..d47898d7495 100644
--- a/samples/client/petstore/javascript-promise/src/api/StoreApi.js
+++ b/samples/client/petstore/javascript-promise/src/api/StoreApi.js
@@ -24,14 +24,12 @@
     /**
      * Returns pet inventories by status
      * Returns a map of status codes to quantities
-     
      *   data is of type: {'String': 'Integer'}
      */
     self.getInventory = function() {
       var postBody = null;
       
 
-      
       var pathParams = {
       };
       var queryParams = {
@@ -51,21 +49,20 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType
       );
-      
+
     }
     
     /**
      * Place an order for a pet
      * 
-     * @param {Order}  body order placed for purchasing the pet
-     
+     * @param {Order} opts['body'] order placed for purchasing the pet
      *   data is of type: Order
      */
-    self.placeOrder = function(body) {
-      var postBody = body;
+    self.placeOrder = function(opts) {
+      opts = opts || {};
+      var postBody = opts['body'];
       
 
-      
       var pathParams = {
       };
       var queryParams = {
@@ -85,14 +82,13 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType
       );
-      
+
     }
     
     /**
      * Find purchase order by ID
      * For valid response try integer IDs with value &lt;= 5 or &gt; 10. Other values will generated exceptions
-     * @param {String}  orderId ID of pet that needs to be fetched
-     
+     * @param {String} orderId ID of pet that needs to be fetched
      *   data is of type: Order
      */
     self.getOrderById = function(orderId) {
@@ -104,7 +100,6 @@
       }
       
 
-      
       var pathParams = {
         'orderId': orderId
       };
@@ -125,14 +120,13 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType
       );
-      
+
     }
     
     /**
      * Delete purchase order by ID
      * For valid response try integer IDs with value &lt; 1000. Anything above 1000 or nonintegers will generate API errors
-     * @param {String}  orderId ID of the order that needs to be deleted
-     
+     * @param {String} orderId ID of the order that needs to be deleted
      */
     self.deleteOrder = function(orderId) {
       var postBody = null;
@@ -143,7 +137,6 @@
       }
       
 
-      
       var pathParams = {
         'orderId': orderId
       };
@@ -164,7 +157,7 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType
       );
-      
+
     }
     
     
diff --git a/samples/client/petstore/javascript-promise/src/api/UserApi.js b/samples/client/petstore/javascript-promise/src/api/UserApi.js
index bb93561ec1b..893ab3e68f1 100644
--- a/samples/client/petstore/javascript-promise/src/api/UserApi.js
+++ b/samples/client/petstore/javascript-promise/src/api/UserApi.js
@@ -24,14 +24,13 @@
     /**
      * Create user
      * This can only be done by the logged in user.
-     * @param {User}  body Created user object
-     
+     * @param {User} opts['body'] Created user object
      */
-    self.createUser = function(body) {
-      var postBody = body;
+    self.createUser = function(opts) {
+      opts = opts || {};
+      var postBody = opts['body'];
       
 
-      
       var pathParams = {
       };
       var queryParams = {
@@ -51,20 +50,19 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType
       );
-      
+
     }
     
     /**
      * Creates list of users with given input array
      * 
-     * @param {[User]}  body List of user object
-     
+     * @param {[User]} opts['body'] List of user object
      */
-    self.createUsersWithArrayInput = function(body) {
-      var postBody = body;
+    self.createUsersWithArrayInput = function(opts) {
+      opts = opts || {};
+      var postBody = opts['body'];
       
 
-      
       var pathParams = {
       };
       var queryParams = {
@@ -84,20 +82,19 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType
       );
-      
+
     }
     
     /**
      * Creates list of users with given input array
      * 
-     * @param {[User]}  body List of user object
-     
+     * @param {[User]} opts['body'] List of user object
      */
-    self.createUsersWithListInput = function(body) {
-      var postBody = body;
+    self.createUsersWithListInput = function(opts) {
+      opts = opts || {};
+      var postBody = opts['body'];
       
 
-      
       var pathParams = {
       };
       var queryParams = {
@@ -117,27 +114,26 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType
       );
-      
+
     }
     
     /**
      * Logs user into the system
      * 
-     * @param {String}  username The user name for login
-     * @param {String}  password The password for login in clear text
-     
+     * @param {String} opts['username'] The user name for login
+     * @param {String} opts['password'] The password for login in clear text
      *   data is of type: 'String'
      */
-    self.loginUser = function(username, password) {
+    self.loginUser = function(opts) {
+      opts = opts || {};
       var postBody = null;
       
 
-      
       var pathParams = {
       };
       var queryParams = {
-        'username': username,
-        'password': password
+        'username': opts['username'],
+        'password': opts['password']
       };
       var headerParams = {
       };
@@ -154,19 +150,17 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType
       );
-      
+
     }
     
     /**
      * Logs out current logged in user session
      * 
-     
      */
     self.logoutUser = function() {
       var postBody = null;
       
 
-      
       var pathParams = {
       };
       var queryParams = {
@@ -186,14 +180,13 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType
       );
-      
+
     }
     
     /**
      * Get user by user name
      * 
-     * @param {String}  username The name that needs to be fetched. Use user1 for testing.
-     
+     * @param {String} username The name that needs to be fetched. Use user1 for testing.
      *   data is of type: User
      */
     self.getUserByName = function(username) {
@@ -205,7 +198,6 @@
       }
       
 
-      
       var pathParams = {
         'username': username
       };
@@ -226,18 +218,18 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType
       );
-      
+
     }
     
     /**
      * Updated user
      * This can only be done by the logged in user.
-     * @param {String}  username name that need to be deleted
-     * @param {User}  body Updated user object
-     
+     * @param {String} username name that need to be deleted
+     * @param {User} opts['body'] Updated user object
      */
-    self.updateUser = function(username, body) {
-      var postBody = body;
+    self.updateUser = function(username, opts) {
+      opts = opts || {};
+      var postBody = opts['body'];
       
       // verify the required parameter 'username' is set
       if (username == null) {
@@ -245,7 +237,6 @@
       }
       
 
-      
       var pathParams = {
         'username': username
       };
@@ -266,14 +257,13 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType
       );
-      
+
     }
     
     /**
      * Delete user
      * This can only be done by the logged in user.
-     * @param {String}  username The name that needs to be deleted
-     
+     * @param {String} username The name that needs to be deleted
      */
     self.deleteUser = function(username) {
       var postBody = null;
@@ -284,7 +274,6 @@
       }
       
 
-      
       var pathParams = {
         'username': username
       };
@@ -305,7 +294,7 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType
       );
-      
+
     }
     
     
diff --git a/samples/client/petstore/javascript-promise/src/model/Pet.js b/samples/client/petstore/javascript-promise/src/model/Pet.js
index 6b43162941c..3b8bdeef123 100644
--- a/samples/client/petstore/javascript-promise/src/model/Pet.js
+++ b/samples/client/petstore/javascript-promise/src/model/Pet.js
@@ -16,7 +16,7 @@
   'use strict';
   
   
-  var Pet = function Pet(photoUrls, name) { 
+  var Pet = function Pet(name, photoUrls) { 
     
     /**
      * datatype: String
diff --git a/samples/client/petstore/javascript-promise/test/api/PetApiTest.js b/samples/client/petstore/javascript-promise/test/api/PetApiTest.js
index f57770999b8..d444529a927 100644
--- a/samples/client/petstore/javascript-promise/test/api/PetApiTest.js
+++ b/samples/client/petstore/javascript-promise/test/api/PetApiTest.js
@@ -29,7 +29,7 @@ var createRandomPet = function() {
 describe('PetApi', function() {
   it('should create and get pet', function(done) {
     var pet = createRandomPet();
-    api.addPet(pet)
+    api.addPet({body: pet})
         .then(function() {
             return api.getPetById(pet.id)
         })
diff --git a/samples/client/petstore/javascript-promise/test/run_tests.html b/samples/client/petstore/javascript-promise/test/run_tests.html
index 2916234bcf3..2f3e3f1e33a 100644
--- a/samples/client/petstore/javascript-promise/test/run_tests.html
+++ b/samples/client/petstore/javascript-promise/test/run_tests.html
@@ -9,6 +9,7 @@
 
   <script src="https://cdn.rawgit.com/jquery/jquery/2.1.4/dist/jquery.min.js"></script>
   <script src="https://cdn.rawgit.com/Automattic/expect.js/0.3.1/index.js"></script>
+  <script src="http://sinonjs.org/releases/sinon-1.17.3.js"></script>
   <script src="https://cdn.rawgit.com/mochajs/mocha/2.2.5/mocha.js"></script>
   <script>
     mocha.setup({
diff --git a/samples/client/petstore/javascript/src/api/PetApi.js b/samples/client/petstore/javascript/src/api/PetApi.js
index 07520e12414..edac9074fbe 100644
--- a/samples/client/petstore/javascript/src/api/PetApi.js
+++ b/samples/client/petstore/javascript/src/api/PetApi.js
@@ -24,14 +24,14 @@
     /**
      * Update an existing pet
      * 
-     * @param {Pet}  body Pet object that needs to be added to the store
+     * @param {Pet} opts['body'] Pet object that needs to be added to the store
      * @param {function} callback the callback function, accepting three arguments: error, data, response
      */
-    self.updatePet = function(body, callback) {
-      var postBody = body;
+    self.updatePet = function(opts, callback) {
+      opts = opts || {};
+      var postBody = opts['body'];
       
 
-      
       var pathParams = {
       };
       var queryParams = {
@@ -51,20 +51,20 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType, callback
       );
-      
+
     }
     
     /**
      * Add a new pet to the store
      * 
-     * @param {Pet}  body Pet object that needs to be added to the store
+     * @param {Pet} opts['body'] Pet object that needs to be added to the store
      * @param {function} callback the callback function, accepting three arguments: error, data, response
      */
-    self.addPet = function(body, callback) {
-      var postBody = body;
+    self.addPet = function(opts, callback) {
+      opts = opts || {};
+      var postBody = opts['body'];
       
 
-      
       var pathParams = {
       };
       var queryParams = {
@@ -84,25 +84,25 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType, callback
       );
-      
+
     }
     
     /**
      * Finds Pets by status
      * Multiple status values can be provided with comma seperated strings
-     * @param {[String]}  status Status values that need to be considered for filter
+     * @param {[String]} opts['status'] Status values that need to be considered for filter
      * @param {function} callback the callback function, accepting three arguments: error, data, response
      *   data is of type: [Pet]
      */
-    self.findPetsByStatus = function(status, callback) {
+    self.findPetsByStatus = function(opts, callback) {
+      opts = opts || {};
       var postBody = null;
       
 
-      
       var pathParams = {
       };
       var queryParams = {
-        'status': this.apiClient.buildCollectionParam(status, 'multi')
+        'status': this.apiClient.buildCollectionParam(opts['status'], 'multi')
       };
       var headerParams = {
       };
@@ -119,25 +119,25 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType, callback
       );
-      
+
     }
     
     /**
      * Finds Pets by tags
      * Muliple tags can be provided with comma seperated strings. Use tag1, tag2, tag3 for testing.
-     * @param {[String]}  tags Tags to filter by
+     * @param {[String]} opts['tags'] Tags to filter by
      * @param {function} callback the callback function, accepting three arguments: error, data, response
      *   data is of type: [Pet]
      */
-    self.findPetsByTags = function(tags, callback) {
+    self.findPetsByTags = function(opts, callback) {
+      opts = opts || {};
       var postBody = null;
       
 
-      
       var pathParams = {
       };
       var queryParams = {
-        'tags': this.apiClient.buildCollectionParam(tags, 'multi')
+        'tags': this.apiClient.buildCollectionParam(opts['tags'], 'multi')
       };
       var headerParams = {
       };
@@ -154,13 +154,13 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType, callback
       );
-      
+
     }
     
     /**
      * Find pet by ID
      * Returns a pet when ID &lt; 10.  ID &gt; 10 or nonintegers will simulate API error conditions
-     * @param {Integer}  petId ID of pet that needs to be fetched
+     * @param {Integer} petId ID of pet that needs to be fetched
      * @param {function} callback the callback function, accepting three arguments: error, data, response
      *   data is of type: Pet
      */
@@ -173,7 +173,6 @@
       }
       
 
-      
       var pathParams = {
         'petId': petId
       };
@@ -194,18 +193,19 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType, callback
       );
-      
+
     }
     
     /**
      * Updates a pet in the store with form data
      * 
-     * @param {String}  petId ID of pet that needs to be updated
-     * @param {String}  name Updated name of the pet
-     * @param {String}  status Updated status of the pet
+     * @param {String} petId ID of pet that needs to be updated
+     * @param {String} opts['name'] Updated name of the pet
+     * @param {String} opts['status'] Updated status of the pet
      * @param {function} callback the callback function, accepting three arguments: error, data, response
      */
-    self.updatePetWithForm = function(petId, name, status, callback) {
+    self.updatePetWithForm = function(petId, opts, callback) {
+      opts = opts || {};
       var postBody = null;
       
       // verify the required parameter 'petId' is set
@@ -214,7 +214,6 @@
       }
       
 
-      
       var pathParams = {
         'petId': petId
       };
@@ -223,8 +222,8 @@
       var headerParams = {
       };
       var formParams = {
-        'name': name,
-        'status': status
+        'name': opts['name'],
+        'status': opts['status']
       };
 
       var authNames = ['petstore_auth'];
@@ -237,17 +236,18 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType, callback
       );
-      
+
     }
     
     /**
      * Deletes a pet
      * 
-     * @param {Integer}  petId Pet id to delete
-     * @param {String}  apiKey 
+     * @param {Integer} petId Pet id to delete
+     * @param {String} opts['apiKey'] 
      * @param {function} callback the callback function, accepting three arguments: error, data, response
      */
-    self.deletePet = function(petId, apiKey, callback) {
+    self.deletePet = function(petId, opts, callback) {
+      opts = opts || {};
       var postBody = null;
       
       // verify the required parameter 'petId' is set
@@ -256,14 +256,13 @@
       }
       
 
-      
       var pathParams = {
         'petId': petId
       };
       var queryParams = {
       };
       var headerParams = {
-        'api_key': apiKey
+        'api_key': opts['apiKey']
       };
       var formParams = {
       };
@@ -278,18 +277,19 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType, callback
       );
-      
+
     }
     
     /**
      * uploads an image
      * 
-     * @param {Integer}  petId ID of pet to update
-     * @param {String}  additionalMetadata Additional data to pass to server
-     * @param {File}  file file to upload
+     * @param {Integer} petId ID of pet to update
+     * @param {String} opts['additionalMetadata'] Additional data to pass to server
+     * @param {File} opts['file'] file to upload
      * @param {function} callback the callback function, accepting three arguments: error, data, response
      */
-    self.uploadFile = function(petId, additionalMetadata, file, callback) {
+    self.uploadFile = function(petId, opts, callback) {
+      opts = opts || {};
       var postBody = null;
       
       // verify the required parameter 'petId' is set
@@ -298,7 +298,6 @@
       }
       
 
-      
       var pathParams = {
         'petId': petId
       };
@@ -307,8 +306,8 @@
       var headerParams = {
       };
       var formParams = {
-        'additionalMetadata': additionalMetadata,
-        'file': file
+        'additionalMetadata': opts['additionalMetadata'],
+        'file': opts['file']
       };
 
       var authNames = ['petstore_auth'];
@@ -321,13 +320,13 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType, callback
       );
-      
+
     }
     
     /**
      * Fake endpoint to test byte array return by &#39;Find pet by ID&#39;
      * Returns a pet when ID &lt; 10.  ID &gt; 10 or nonintegers will simulate API error conditions
-     * @param {Integer}  petId ID of pet that needs to be fetched
+     * @param {Integer} petId ID of pet that needs to be fetched
      * @param {function} callback the callback function, accepting three arguments: error, data, response
      *   data is of type: 'String'
      */
@@ -340,7 +339,6 @@
       }
       
 
-      
       var pathParams = {
         'petId': petId
       };
@@ -361,20 +359,20 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType, callback
       );
-      
+
     }
     
     /**
      * Fake endpoint to test byte array in body parameter for adding a new pet to the store
      * 
-     * @param {String}  body Pet object in the form of byte array
+     * @param {String} opts['body'] Pet object in the form of byte array
      * @param {function} callback the callback function, accepting three arguments: error, data, response
      */
-    self.addPetUsingByteArray = function(body, callback) {
-      var postBody = body;
+    self.addPetUsingByteArray = function(opts, callback) {
+      opts = opts || {};
+      var postBody = opts['body'];
       
 
-      
       var pathParams = {
       };
       var queryParams = {
@@ -394,7 +392,7 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType, callback
       );
-      
+
     }
     
     
diff --git a/samples/client/petstore/javascript/src/api/StoreApi.js b/samples/client/petstore/javascript/src/api/StoreApi.js
index cf9bc1c78af..6abe687b7f4 100644
--- a/samples/client/petstore/javascript/src/api/StoreApi.js
+++ b/samples/client/petstore/javascript/src/api/StoreApi.js
@@ -31,7 +31,6 @@
       var postBody = null;
       
 
-      
       var pathParams = {
       };
       var queryParams = {
@@ -51,21 +50,21 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType, callback
       );
-      
+
     }
     
     /**
      * Place an order for a pet
      * 
-     * @param {Order}  body order placed for purchasing the pet
+     * @param {Order} opts['body'] order placed for purchasing the pet
      * @param {function} callback the callback function, accepting three arguments: error, data, response
      *   data is of type: Order
      */
-    self.placeOrder = function(body, callback) {
-      var postBody = body;
+    self.placeOrder = function(opts, callback) {
+      opts = opts || {};
+      var postBody = opts['body'];
       
 
-      
       var pathParams = {
       };
       var queryParams = {
@@ -85,13 +84,13 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType, callback
       );
-      
+
     }
     
     /**
      * Find purchase order by ID
      * For valid response try integer IDs with value &lt;= 5 or &gt; 10. Other values will generated exceptions
-     * @param {String}  orderId ID of pet that needs to be fetched
+     * @param {String} orderId ID of pet that needs to be fetched
      * @param {function} callback the callback function, accepting three arguments: error, data, response
      *   data is of type: Order
      */
@@ -104,7 +103,6 @@
       }
       
 
-      
       var pathParams = {
         'orderId': orderId
       };
@@ -125,13 +123,13 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType, callback
       );
-      
+
     }
     
     /**
      * Delete purchase order by ID
      * For valid response try integer IDs with value &lt; 1000. Anything above 1000 or nonintegers will generate API errors
-     * @param {String}  orderId ID of the order that needs to be deleted
+     * @param {String} orderId ID of the order that needs to be deleted
      * @param {function} callback the callback function, accepting three arguments: error, data, response
      */
     self.deleteOrder = function(orderId, callback) {
@@ -143,7 +141,6 @@
       }
       
 
-      
       var pathParams = {
         'orderId': orderId
       };
@@ -164,7 +161,7 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType, callback
       );
-      
+
     }
     
     
diff --git a/samples/client/petstore/javascript/src/api/UserApi.js b/samples/client/petstore/javascript/src/api/UserApi.js
index cc9cd928f11..4886330d3d6 100644
--- a/samples/client/petstore/javascript/src/api/UserApi.js
+++ b/samples/client/petstore/javascript/src/api/UserApi.js
@@ -24,14 +24,14 @@
     /**
      * Create user
      * This can only be done by the logged in user.
-     * @param {User}  body Created user object
+     * @param {User} opts['body'] Created user object
      * @param {function} callback the callback function, accepting three arguments: error, data, response
      */
-    self.createUser = function(body, callback) {
-      var postBody = body;
+    self.createUser = function(opts, callback) {
+      opts = opts || {};
+      var postBody = opts['body'];
       
 
-      
       var pathParams = {
       };
       var queryParams = {
@@ -51,20 +51,20 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType, callback
       );
-      
+
     }
     
     /**
      * Creates list of users with given input array
      * 
-     * @param {[User]}  body List of user object
+     * @param {[User]} opts['body'] List of user object
      * @param {function} callback the callback function, accepting three arguments: error, data, response
      */
-    self.createUsersWithArrayInput = function(body, callback) {
-      var postBody = body;
+    self.createUsersWithArrayInput = function(opts, callback) {
+      opts = opts || {};
+      var postBody = opts['body'];
       
 
-      
       var pathParams = {
       };
       var queryParams = {
@@ -84,20 +84,20 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType, callback
       );
-      
+
     }
     
     /**
      * Creates list of users with given input array
      * 
-     * @param {[User]}  body List of user object
+     * @param {[User]} opts['body'] List of user object
      * @param {function} callback the callback function, accepting three arguments: error, data, response
      */
-    self.createUsersWithListInput = function(body, callback) {
-      var postBody = body;
+    self.createUsersWithListInput = function(opts, callback) {
+      opts = opts || {};
+      var postBody = opts['body'];
       
 
-      
       var pathParams = {
       };
       var queryParams = {
@@ -117,27 +117,27 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType, callback
       );
-      
+
     }
     
     /**
      * Logs user into the system
      * 
-     * @param {String}  username The user name for login
-     * @param {String}  password The password for login in clear text
+     * @param {String} opts['username'] The user name for login
+     * @param {String} opts['password'] The password for login in clear text
      * @param {function} callback the callback function, accepting three arguments: error, data, response
      *   data is of type: 'String'
      */
-    self.loginUser = function(username, password, callback) {
+    self.loginUser = function(opts, callback) {
+      opts = opts || {};
       var postBody = null;
       
 
-      
       var pathParams = {
       };
       var queryParams = {
-        'username': username,
-        'password': password
+        'username': opts['username'],
+        'password': opts['password']
       };
       var headerParams = {
       };
@@ -154,7 +154,7 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType, callback
       );
-      
+
     }
     
     /**
@@ -166,7 +166,6 @@
       var postBody = null;
       
 
-      
       var pathParams = {
       };
       var queryParams = {
@@ -186,13 +185,13 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType, callback
       );
-      
+
     }
     
     /**
      * Get user by user name
      * 
-     * @param {String}  username The name that needs to be fetched. Use user1 for testing.
+     * @param {String} username The name that needs to be fetched. Use user1 for testing.
      * @param {function} callback the callback function, accepting three arguments: error, data, response
      *   data is of type: User
      */
@@ -205,7 +204,6 @@
       }
       
 
-      
       var pathParams = {
         'username': username
       };
@@ -226,18 +224,19 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType, callback
       );
-      
+
     }
     
     /**
      * Updated user
      * This can only be done by the logged in user.
-     * @param {String}  username name that need to be deleted
-     * @param {User}  body Updated user object
+     * @param {String} username name that need to be deleted
+     * @param {User} opts['body'] Updated user object
      * @param {function} callback the callback function, accepting three arguments: error, data, response
      */
-    self.updateUser = function(username, body, callback) {
-      var postBody = body;
+    self.updateUser = function(username, opts, callback) {
+      opts = opts || {};
+      var postBody = opts['body'];
       
       // verify the required parameter 'username' is set
       if (username == null) {
@@ -245,7 +244,6 @@
       }
       
 
-      
       var pathParams = {
         'username': username
       };
@@ -266,13 +264,13 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType, callback
       );
-      
+
     }
     
     /**
      * Delete user
      * This can only be done by the logged in user.
-     * @param {String}  username The name that needs to be deleted
+     * @param {String} username The name that needs to be deleted
      * @param {function} callback the callback function, accepting three arguments: error, data, response
      */
     self.deleteUser = function(username, callback) {
@@ -284,7 +282,6 @@
       }
       
 
-      
       var pathParams = {
         'username': username
       };
@@ -305,7 +302,7 @@
         pathParams, queryParams, headerParams, formParams, postBody,
         authNames, contentTypes, accepts, returnType, callback
       );
-      
+
     }
     
     
diff --git a/samples/client/petstore/javascript/src/model/Pet.js b/samples/client/petstore/javascript/src/model/Pet.js
index 6b43162941c..3b8bdeef123 100644
--- a/samples/client/petstore/javascript/src/model/Pet.js
+++ b/samples/client/petstore/javascript/src/model/Pet.js
@@ -16,7 +16,7 @@
   'use strict';
   
   
-  var Pet = function Pet(photoUrls, name) { 
+  var Pet = function Pet(name, photoUrls) { 
     
     /**
      * datatype: String
diff --git a/samples/client/petstore/javascript/test/api/PetApiTest.js b/samples/client/petstore/javascript/test/api/PetApiTest.js
index 9385cf2701b..a2b64bec4b6 100644
--- a/samples/client/petstore/javascript/test/api/PetApiTest.js
+++ b/samples/client/petstore/javascript/test/api/PetApiTest.js
@@ -29,7 +29,7 @@ var createRandomPet = function() {
 describe('PetApi', function() {
   it('should create and get pet', function(done) {
     var pet = createRandomPet();
-    api.addPet(pet, function(error) {
+    api.addPet({body: pet}, function(error) {
       if (error) throw error;
 
       api.getPetById(pet.id, function(error, fetched, response) {