allow consumers to override the Promise implementation

README.md

@@ -190,9 +190,21 @@ Here are some applications that use this library (presented by framework in alph
 
 ## Dependencies
 
-This library doesn't have any external dependencies, but it expects to be run in a browser (i.e. not Node.js). Since v1.5 asynchronous functions like `loadScript()` and `loadModules()` return [`Promise`s](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise), so if your application has to support [browers that don't support Promise (i.e. IE)](https://caniuse.com/#search=promise), then you should consider using a [Promise polyfill](https://www.google.com/search?q=promise+polyfill), ideally [only when needed](https://philipwalton.com/articles/loading-polyfills-only-when-needed/).
+This library doesn't have any external dependencies, but it expects to be run in a browser (i.e. not Node.js). Since v1.5 asynchronous functions like `loadScript()` and `loadModules()` return [`Promise`s](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise), so if your application has to support [browers that don't support Promise (i.e. IE)](https://caniuse.com/#search=promise) you have a few options.
 
-Alternatively, you can still use `bootstrap()` and `dojoRequire()` which are the callback-based equivalents of the above functions. See the [v1.4.0 documentation](https://github.com/Esri/esri-loader/blob/v1.4.0/README.md#usage) for how to use the callback-based API, but _keep in mind that these functions have been deprecated and will be removed at the next major release_.
+If there's already a Promise implementation loaded on the page you can configure esri-loader to use that implementation. For example, in [ember-esri-loader](https://github.com/Esri/ember-esri-loader), we configure esri-loader to use the RSVP Promise implementation included with Ember.js.
+
+```js
+  init () {
+    this._super(...arguments);
+    // have esriLoader use Ember's RSVP promise
+    esriLoader.utils.Promise = Ember.RSVP.Promise;
+  },
+```
+
+Otherwise, you should consider using a [Promise polyfill](https://www.google.com/search?q=promise+polyfill), ideally [only when needed](https://philipwalton.com/articles/loading-polyfills-only-when-needed/).
+
+Finally, for now you can still use `bootstrap()` and `dojoRequire()` which are the callback-based equivalents of the above functions. See the [v1.4.0 documentation](https://github.com/Esri/esri-loader/blob/v1.4.0/README.md#usage) for how to use the callback-based API, but _keep in mind that these functions have been deprecated and will be removed at the next major release_.
 
 ## Issues
 

src/esri-loader.ts

@@ -75,6 +75,11 @@ export interface IBootstrapOptions {
   dojoConfig?: { [propName: string]: any };
 }
 
+// allow consuming libraries to provide their own Promise implementations
+export const utils = {
+  Promise: window['Promise']
+};
+
 export interface ILoadScriptOptions {
   url?: string;
   // NOTE: stole the type definition for dojoConfig from:
@@ -96,7 +101,7 @@ export function loadScript(options: ILoadScriptOptions = {}): Promise<HTMLScript
     options.url = DEFAULT_URL;
   }
 
-  return new Promise((resolve, reject) => {
+  return new utils.Promise((resolve, reject) => {
     let script = getScript();
     if (script) {
       // the API is already loaded or in the process of loading...
@@ -146,7 +151,7 @@ export function loadScript(options: ILoadScriptOptions = {}): Promise<HTMLScript
 
 // wrap dojo's require() in a promise
 function requireModules(modules: string[]): Promise<any[]> {
-  return new Promise((resolve, reject) => {
+  return new utils.Promise((resolve, reject) => {
     // If something goes wrong loading the esri/dojo scripts, reject with the error.
     const errorHandler = window['require'].on('error', reject);
     window['require'](modules, (...args) => {
@@ -247,6 +252,7 @@ export default {
   isLoaded,
   loadScript,
   loadModules,
+  utils,
   // TODO: remove these the next major release
   bootstrap,
   dojoRequire