Add non-standardized timeout option to the fetch API

Libraries/Fetch/__tests__/fetch-test.js

@@ -0,0 +1,34 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+'use strict';
+
+jest.dontMock('fetch');
+const fetch = require('fetch').fetch;
+
+// Let fetch pick up a XMLHttpRequest mock from global scope
+global.XMLHttpRequest = jest.fn();
+
+describe('fetch', () => {
+ it('should only set XMLHttpRequest timeout if set in options', () => {
+ const url = 'http://foobar/';
+
+ fetch(url).then(() => {}, () => {});
+ jest.runAllTicks();
+ expect(XMLHttpRequest.mock.instances.length).toBe(1);
+ expect(XMLHttpRequest.mock.instances[0].timeout).toBeUndefined();
+
+ XMLHttpRequest.mockClear();
+
+ fetch(url, {timeout: 42}).then(() => {}, () => {});
+ jest.runAllTicks();
+ expect(XMLHttpRequest.mock.instances.length).toBe(1);
+ expect(XMLHttpRequest.mock.instances[0].timeout).toBe(42);
+ });
+});

Libraries/Fetch/fetch.js

@@ -283,6 +283,7 @@ var self = {};
  this.method = normalizeMethod(options.method || this.method || 'GET')
  this.mode = options.mode || this.mode || null
  this.referrer = null
+ this.timeout = options.timeout || null
 
  if ((this.method === 'GET' || this.method === 'HEAD') && body) {
  throw new TypeError('Body not allowed for GET or HEAD requests')
@@ -376,6 +377,12 @@ var self = {};
 
  var xhr = new XMLHttpRequest()
 
+ if (request.timeout) {
+ // Only set XMLHttpRequest timeout if set in options to
+ // avoid overriding the XMLHttpRequest default timeout
+ xhr.timeout = request.timeout
+ }
+
  function responseURL() {
  if ('responseURL' in xhr) {
  return xhr.responseURL

docs/Network.md

@@ -35,6 +35,19 @@ fetch('https://mywebsite.com/endpoint/', {
 })
 ```
 
+A non-standardized timeout option is available in the React Native implementation of the fetch API:
+
+```js
+fetch('https://mywebsite.com/endpoint/', {
+ timeout: 30000
+})
+```
+
+Notes:
+ - The timeout is specified in milliseconds.
+ - The default if unspecified is **no timeout**.
+ - The returned Promise is rejected if the request timeout.
+
 #### Async
 
 `fetch` returns a [Promise](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise) that can be processed in two ways: