angular/packages/zone.js/NON-STANDARD-APIS.md

Zone.js's support for non standard apis

Zone.js patches most standard APIs, such as DOM event listeners and XMLHttpRequest in the browser, as well as EventEmitter and the fs API in Node.js, so they can operate within a zone.

But there are still many non-standard APIs that are not patched by default, such as MediaQuery, Notification, and WebAudio. This page provides updates on the current state of zone support for Angular APIs.

Currently Supported Non-Standard Web APIs

• MediaQuery
• Notification

Currently Supported Polyfills

• WebComponents

Usage:

<script src="webcomponents-lite.js"></script>
<script src="node_modules/zone.js/bundles/zone.umd.js"></script>
<script src="node_modules/zone.js/bundles/webapis-shadydom.umd.js"></script>

Currently Supported Non-Standard Node.js APIs

• (empty)

Currently Supported Non-Standard Common APIs

• Bluebird Promise

Browser Usage:

<script src="zone.js"></script>
<script src="bluebird.js"></script>
<script src="zone-bluebird.js"></script>
<script>
  Zone[Zone['__symbol__']('bluebird')](Promise);
</script>

After completing those steps, window.Promise will be replaced by Bluebird Promise and will also be zone-aware.

Angular Usage:

In polyfills.ts, import the zone-bluebird package:

import 'zone.js'; // Included with Angular CLI.
import 'zone.js/plugins/zone-bluebird';

In main.ts, patch bluebird:

/// <reference types="zone.js" />

bootstrapApplication(AppComponent, appConfig)
  .then(() => {
    import('bluebird').then((Bluebird) => {
      const bluebirdSymbol = Zone.__symbol__('bluebird');
      const patchBluebirdFn = (Zone as any)[bluebirdSymbol];
      patchBluebirdFn(Bluebird.default);
    });
  })
  .catch((err) => console.error(err));

After this step, window.Promise will be replaced by Bluebird's Promise, and the callback for Bluebird.then will be executed within the Angular zone.

Node Sample Usage:

require('zone.js');
const Bluebird = require('bluebird');
require('zone.js/plugins/zone-bluebird');

const bluebirdSymbol = Zone.__symbol__('bluebird');
const patchBluebirdFn = (Zone as any)[bluebirdSymbol];
patchBluebirdFn(Bluebird);

Zone.current
  .fork({
    name: 'bluebird',
  })
  .run(() => {
    Bluebird.resolve(1).then((result) => {
      console.log('result ', result, 'Zone', Zone.current.name);
    });
  });

In a Node.js environment, you can choose to use Bluebird Promise as global.Promise or ZoneAwarePromise as global.Promise.

To run the jasmine test cases of bluebird:

npm install bluebird

Then modify test/node_tests.ts and remove the comment of the following line:

//import './extra/bluebird.spec';

Others

• Cordova

patch cordova.exec API

cordova.exec(success, error, service, action, args);

success and error will be patched with Zone.wrap.

to load the patch, you should load in the following order.

<script src="zone.js"></script>
<script src="cordova.js"></script>
<script src="zone-patch-cordova.js"></script>

Usage

By default, support for those APIs is not included in zone.js or zone-node.js. If you want to enable support for these APIs, you will need to load the files yourself.

For example, if you want to add a MediaQuery patch, you should do it like this:

<script src="path/zone.js"></script>
<script src="path/webapis-media-query.js"></script>

• RxJS

zone.js also provides an rxjs patch to ensure that RxJS Observables, Subscriptions, and Operators run in the correct zone. For details, please refer to pull request 843. The following sample code illustrates this concept:

const constructorZone = Zone.current.fork({name: 'constructor'});
const subscriptionZone = Zone.current.fork({name: 'subscription'});
const operatorZone = Zone.current.fork({name: 'operator'});

let observable;
let subscriber;

constructorZone.run(() => {
  observable = new Observable((_subscriber) => {
    subscriber = _subscriber;
    console.log('current zone when construct observable:', Zone.current.name); // will output constructor.
    return () => {
      console.log('current zone when unsubscribe observable:', Zone.current.name); // will output constructor.
    };
  });
});

subscriptionZone.run(() => {
  observable.subscribe({
    next: () => {
      console.log('current zone when subscription next', Zone.current.name); // will output subscription.
    },
    error: () => {
      console.log('current zone when subscription error', Zone.current.name); // will output subscription.
    },
    complete: () => {
      console.log('current zone when subscription complete', Zone.current.name); // will output subscription.
    },
  });
});

operatorZone.run(() => {
  observable.map(() => {
    console.log('current zone when map operator', Zone.current.name); // will output operator.
  });
});

Currently basically everything the rxjs API includes

• Observable
• Subscription
• Subscriber
• Operators
• Scheduler

is patched, so each asynchronous call will run in the correct zone.

Usage.

For example, in an Angular application, you can load this patch in your app.module.ts.

import 'zone.js/plugins/zone-patch-rxjs';

• electron

In electron, we patched the following APIs with zone.js

1. Browser API
2. NodeJS
3. Electron Native API

Usage.

add following line into polyfill.ts after loading zone-mix.

//import 'zone.js'; // originally added by angular-cli, comment it out
import 'zone.js/mix'; // add zone-mix to patch both Browser and Nodejs
import 'zone.js/plugins/zone-patch-electron'; // add zone-patch-electron to patch Electron native API

there is a sample repo zone-electron.

• socket.io-client

user need to patch io themselves just like following code.

<script src="socket.io-client/dist/socket.io.js"></script>
<script src="zone.js/bundles/zone.umd.js"></script>
<script src="zone.js/bundles/zone-patch-socket-io.js"></script>
<script>
  // patch io here
  const patchSocketIOFn = Zone[Zone.__symbol__('socketio')];
  patchSocketIOFn(io);
</script>

Please refer to the sample repository zone-socketio for detailed usage.

• jsonp

Usage.

A helper method is provided to patch JSONP. Since JSONP has many implementations, the user needs to supply the information necessary for JSON to send and callback in the zone.

There is a sample repository, zone-jsonp, available here. The sample usage is as follows:

import 'zone.js/plugins/zone-patch-jsonp';

Zone['__zone_symbol__jsonp']({
  jsonp: getJSONP,
  sendFuncName: 'send',
  successFuncName: 'jsonpSuccessCallback',
  failedFuncName: 'jsonpFailedCallback',
});

• ResizeObserver

Currently, only Chrome 64 natively supports this feature. You can add the following line to polyfill.ts after loading zone.js:

import 'zone.js';
import 'zone.js/plugins/zone-patch-resize-observer';

There is a sample repository, zone-resize-observer, available here.