diff --git a/modules/swagger-codegen/src/main/resources/TypeScript-Fetch/api.mustache b/modules/swagger-codegen/src/main/resources/TypeScript-Fetch/api.mustache
index 8f61823795d..74c93831336 100644
--- a/modules/swagger-codegen/src/main/resources/TypeScript-Fetch/api.mustache
+++ b/modules/swagger-codegen/src/main/resources/TypeScript-Fetch/api.mustache
@@ -7,7 +7,7 @@ import * as isomorphicFetch from "isomorphic-fetch";
 import * as assign from "core-js/library/fn/object/assign";
 {{/supportsES6}}
 
-import { Configuration } from './configuration';
+import { Configuration } from "./configuration";
 
 interface Dictionary<T> { [index: string]: T; }
 export interface FetchAPI { (url: string, init?: any): Promise<any>; }
@@ -126,14 +126,14 @@ export const {{classname}}FetchParamCreator = {
 {{#isKeyInHeader}}
         if (configuration.apiKey && configuration.apiKey.{{keyParamName}}) {
             fetchOptions.headers = {{#supportsES6}}Object.{{/supportsES6}}assign({
-                    '{{keyParamName}}': configuration.apiKey.{{keyParamName}},
+                    "{{keyParamName}}": configuration.apiKey.{{keyParamName}},
                     }, contentTypeHeader);
         }
 {{/isKeyInHeader}}
 {{#isKeyInQuery}}
         if (configuration.apiKey && configuration.apiKey.{{keyParamName}}) {
             urlObj.query = {{#supportsES6}}Object.{{/supportsES6}}assign({}, urlObj.query, {
-                    '{{keyParamName}}': configuration.apiKey.{{keyParamName}},
+                    "{{keyParamName}}": configuration.apiKey.{{keyParamName}},
                     });
         }
 {{/isKeyInQuery}}
@@ -142,7 +142,7 @@ export const {{classname}}FetchParamCreator = {
         // http basic authentication required
         if (configuration.username || configuration.password) {
             fetchOptions.headers = {{#supportsES6}}Object.{{/supportsES6}}assign({
-                    'Authorization': 'Basic ' + btoa(configuration.username + ':' + configuration.password),
+                    "Authorization": "Basic " + btoa(configuration.username + ":" + configuration.password),
                     }, contentTypeHeader);
         }
 {{/isBasic}}
@@ -150,7 +150,7 @@ export const {{classname}}FetchParamCreator = {
         // oauth required
         if (configuration.accessToken) {
             fetchOptions.headers = {{#supportsES6}}Object.{{/supportsES6}}assign({
-                    'Authorization': 'Bearer ' + configuration.accessToken,
+                    "Authorization": "Bearer " + configuration.accessToken,
                     }, contentTypeHeader);
         }
 {{/isOAuth}}
diff --git a/samples/client/petstore/typescript-fetch/builds/default/api.ts b/samples/client/petstore/typescript-fetch/builds/default/api.ts
index 0fd54b5ec1b..0930b8db510 100644
--- a/samples/client/petstore/typescript-fetch/builds/default/api.ts
+++ b/samples/client/petstore/typescript-fetch/builds/default/api.ts
@@ -16,7 +16,7 @@ import * as url from "url";
 import * as isomorphicFetch from "isomorphic-fetch";
 import * as assign from "core-js/library/fn/object/assign";
 
-import { Configuration } from './configuration';
+import { Configuration } from "./configuration";
 
 interface Dictionary<T> { [index: string]: T; }
 export interface FetchAPI { (url: string, init?: any): Promise<any>; }
@@ -146,7 +146,7 @@ export const PetApiFetchParamCreator = {
         // oauth required
         if (configuration.accessToken) {
             fetchOptions.headers = assign({
-                    'Authorization': 'Bearer ' + configuration.accessToken,
+                    "Authorization": "Bearer " + configuration.accessToken,
                     }, contentTypeHeader);
         }
 
@@ -179,7 +179,7 @@ export const PetApiFetchParamCreator = {
         // oauth required
         if (configuration.accessToken) {
             fetchOptions.headers = assign({
-                    'Authorization': 'Bearer ' + configuration.accessToken,
+                    "Authorization": "Bearer " + configuration.accessToken,
                     }, contentTypeHeader);
         }
 
@@ -213,7 +213,7 @@ export const PetApiFetchParamCreator = {
         // oauth required
         if (configuration.accessToken) {
             fetchOptions.headers = assign({
-                    'Authorization': 'Bearer ' + configuration.accessToken,
+                    "Authorization": "Bearer " + configuration.accessToken,
                     }, contentTypeHeader);
         }
 
@@ -247,7 +247,7 @@ export const PetApiFetchParamCreator = {
         // oauth required
         if (configuration.accessToken) {
             fetchOptions.headers = assign({
-                    'Authorization': 'Bearer ' + configuration.accessToken,
+                    "Authorization": "Bearer " + configuration.accessToken,
                     }, contentTypeHeader);
         }
 
@@ -278,7 +278,7 @@ export const PetApiFetchParamCreator = {
         // authentication (api_key) required
         if (configuration.apiKey && configuration.apiKey.api_key) {
             fetchOptions.headers = assign({
-                    'api_key': configuration.apiKey.api_key,
+                    "api_key": configuration.apiKey.api_key,
                     }, contentTypeHeader);
         }
 
@@ -313,7 +313,7 @@ export const PetApiFetchParamCreator = {
         // oauth required
         if (configuration.accessToken) {
             fetchOptions.headers = assign({
-                    'Authorization': 'Bearer ' + configuration.accessToken,
+                    "Authorization": "Bearer " + configuration.accessToken,
                     }, contentTypeHeader);
         }
 
@@ -352,7 +352,7 @@ export const PetApiFetchParamCreator = {
         // oauth required
         if (configuration.accessToken) {
             fetchOptions.headers = assign({
-                    'Authorization': 'Bearer ' + configuration.accessToken,
+                    "Authorization": "Bearer " + configuration.accessToken,
                     }, contentTypeHeader);
         }
 
@@ -391,7 +391,7 @@ export const PetApiFetchParamCreator = {
         // oauth required
         if (configuration.accessToken) {
             fetchOptions.headers = assign({
-                    'Authorization': 'Bearer ' + configuration.accessToken,
+                    "Authorization": "Bearer " + configuration.accessToken,
                     }, contentTypeHeader);
         }
 
@@ -747,7 +747,7 @@ export const StoreApiFetchParamCreator = {
         // authentication (api_key) required
         if (configuration.apiKey && configuration.apiKey.api_key) {
             fetchOptions.headers = assign({
-                    'api_key': configuration.apiKey.api_key,
+                    "api_key": configuration.apiKey.api_key,
                     }, contentTypeHeader);
         }
 
diff --git a/samples/client/petstore/typescript-fetch/builds/es6-target/api.ts b/samples/client/petstore/typescript-fetch/builds/es6-target/api.ts
index 2df0c3d1a56..31a93606ae2 100644
--- a/samples/client/petstore/typescript-fetch/builds/es6-target/api.ts
+++ b/samples/client/petstore/typescript-fetch/builds/es6-target/api.ts
@@ -15,7 +15,7 @@ import * as url from "url";
 
 import * as isomorphicFetch from "isomorphic-fetch";
 
-import { Configuration } from './configuration';
+import { Configuration } from "./configuration";
 
 interface Dictionary<T> { [index: string]: T; }
 export interface FetchAPI { (url: string, init?: any): Promise<any>; }
@@ -145,7 +145,7 @@ export const PetApiFetchParamCreator = {
         // oauth required
         if (configuration.accessToken) {
             fetchOptions.headers = Object.assign({
-                    'Authorization': 'Bearer ' + configuration.accessToken,
+                    "Authorization": "Bearer " + configuration.accessToken,
                     }, contentTypeHeader);
         }
 
@@ -178,7 +178,7 @@ export const PetApiFetchParamCreator = {
         // oauth required
         if (configuration.accessToken) {
             fetchOptions.headers = Object.assign({
-                    'Authorization': 'Bearer ' + configuration.accessToken,
+                    "Authorization": "Bearer " + configuration.accessToken,
                     }, contentTypeHeader);
         }
 
@@ -212,7 +212,7 @@ export const PetApiFetchParamCreator = {
         // oauth required
         if (configuration.accessToken) {
             fetchOptions.headers = Object.assign({
-                    'Authorization': 'Bearer ' + configuration.accessToken,
+                    "Authorization": "Bearer " + configuration.accessToken,
                     }, contentTypeHeader);
         }
 
@@ -246,7 +246,7 @@ export const PetApiFetchParamCreator = {
         // oauth required
         if (configuration.accessToken) {
             fetchOptions.headers = Object.assign({
-                    'Authorization': 'Bearer ' + configuration.accessToken,
+                    "Authorization": "Bearer " + configuration.accessToken,
                     }, contentTypeHeader);
         }
 
@@ -277,7 +277,7 @@ export const PetApiFetchParamCreator = {
         // authentication (api_key) required
         if (configuration.apiKey && configuration.apiKey.api_key) {
             fetchOptions.headers = Object.assign({
-                    'api_key': configuration.apiKey.api_key,
+                    "api_key": configuration.apiKey.api_key,
                     }, contentTypeHeader);
         }
 
@@ -312,7 +312,7 @@ export const PetApiFetchParamCreator = {
         // oauth required
         if (configuration.accessToken) {
             fetchOptions.headers = Object.assign({
-                    'Authorization': 'Bearer ' + configuration.accessToken,
+                    "Authorization": "Bearer " + configuration.accessToken,
                     }, contentTypeHeader);
         }
 
@@ -351,7 +351,7 @@ export const PetApiFetchParamCreator = {
         // oauth required
         if (configuration.accessToken) {
             fetchOptions.headers = Object.assign({
-                    'Authorization': 'Bearer ' + configuration.accessToken,
+                    "Authorization": "Bearer " + configuration.accessToken,
                     }, contentTypeHeader);
         }
 
@@ -390,7 +390,7 @@ export const PetApiFetchParamCreator = {
         // oauth required
         if (configuration.accessToken) {
             fetchOptions.headers = Object.assign({
-                    'Authorization': 'Bearer ' + configuration.accessToken,
+                    "Authorization": "Bearer " + configuration.accessToken,
                     }, contentTypeHeader);
         }
 
@@ -746,7 +746,7 @@ export const StoreApiFetchParamCreator = {
         // authentication (api_key) required
         if (configuration.apiKey && configuration.apiKey.api_key) {
             fetchOptions.headers = Object.assign({
-                    'api_key': configuration.apiKey.api_key,
+                    "api_key": configuration.apiKey.api_key,
                     }, contentTypeHeader);
         }
 
diff --git a/samples/client/petstore/typescript-fetch/builds/with-npm-version/api.ts b/samples/client/petstore/typescript-fetch/builds/with-npm-version/api.ts
index 0fd54b5ec1b..0930b8db510 100644
--- a/samples/client/petstore/typescript-fetch/builds/with-npm-version/api.ts
+++ b/samples/client/petstore/typescript-fetch/builds/with-npm-version/api.ts
@@ -16,7 +16,7 @@ import * as url from "url";
 import * as isomorphicFetch from "isomorphic-fetch";
 import * as assign from "core-js/library/fn/object/assign";
 
-import { Configuration } from './configuration';
+import { Configuration } from "./configuration";
 
 interface Dictionary<T> { [index: string]: T; }
 export interface FetchAPI { (url: string, init?: any): Promise<any>; }
@@ -146,7 +146,7 @@ export const PetApiFetchParamCreator = {
         // oauth required
         if (configuration.accessToken) {
             fetchOptions.headers = assign({
-                    'Authorization': 'Bearer ' + configuration.accessToken,
+                    "Authorization": "Bearer " + configuration.accessToken,
                     }, contentTypeHeader);
         }
 
@@ -179,7 +179,7 @@ export const PetApiFetchParamCreator = {
         // oauth required
         if (configuration.accessToken) {
             fetchOptions.headers = assign({
-                    'Authorization': 'Bearer ' + configuration.accessToken,
+                    "Authorization": "Bearer " + configuration.accessToken,
                     }, contentTypeHeader);
         }
 
@@ -213,7 +213,7 @@ export const PetApiFetchParamCreator = {
         // oauth required
         if (configuration.accessToken) {
             fetchOptions.headers = assign({
-                    'Authorization': 'Bearer ' + configuration.accessToken,
+                    "Authorization": "Bearer " + configuration.accessToken,
                     }, contentTypeHeader);
         }
 
@@ -247,7 +247,7 @@ export const PetApiFetchParamCreator = {
         // oauth required
         if (configuration.accessToken) {
             fetchOptions.headers = assign({
-                    'Authorization': 'Bearer ' + configuration.accessToken,
+                    "Authorization": "Bearer " + configuration.accessToken,
                     }, contentTypeHeader);
         }
 
@@ -278,7 +278,7 @@ export const PetApiFetchParamCreator = {
         // authentication (api_key) required
         if (configuration.apiKey && configuration.apiKey.api_key) {
             fetchOptions.headers = assign({
-                    'api_key': configuration.apiKey.api_key,
+                    "api_key": configuration.apiKey.api_key,
                     }, contentTypeHeader);
         }
 
@@ -313,7 +313,7 @@ export const PetApiFetchParamCreator = {
         // oauth required
         if (configuration.accessToken) {
             fetchOptions.headers = assign({
-                    'Authorization': 'Bearer ' + configuration.accessToken,
+                    "Authorization": "Bearer " + configuration.accessToken,
                     }, contentTypeHeader);
         }
 
@@ -352,7 +352,7 @@ export const PetApiFetchParamCreator = {
         // oauth required
         if (configuration.accessToken) {
             fetchOptions.headers = assign({
-                    'Authorization': 'Bearer ' + configuration.accessToken,
+                    "Authorization": "Bearer " + configuration.accessToken,
                     }, contentTypeHeader);
         }
 
@@ -391,7 +391,7 @@ export const PetApiFetchParamCreator = {
         // oauth required
         if (configuration.accessToken) {
             fetchOptions.headers = assign({
-                    'Authorization': 'Bearer ' + configuration.accessToken,
+                    "Authorization": "Bearer " + configuration.accessToken,
                     }, contentTypeHeader);
         }
 
@@ -747,7 +747,7 @@ export const StoreApiFetchParamCreator = {
         // authentication (api_key) required
         if (configuration.apiKey && configuration.apiKey.api_key) {
             fetchOptions.headers = assign({
-                    'api_key': configuration.apiKey.api_key,
+                    "api_key": configuration.apiKey.api_key,
                     }, contentTypeHeader);
         }