angular-cn/modules/@angular/examples/common/pipes/ts/async_pipe.ts

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/**
* @license
* Copyright Google Inc. All Rights Reserved.
*
* Use of this source code is governed by an MIT-style license that can be
* found in the LICENSE file at https://angular.io/license
*/
import {Component} from '@angular/core';
import {Observable} from 'rxjs/Observable';
import {Subscriber} from 'rxjs/Subscriber';
// #docregion AsyncPipePromise
@Component({
selector: 'async-promise-pipe',
template: `<div>
<code>promise|async</code>:
<button (click)="clicked()">{{ arrived ? 'Reset' : 'Resolve' }}</button>
<span>Wait for it... {{ greeting | async }}</span>
</div>`
})
export class AsyncPromisePipeComponent {
greeting: Promise<string> = null;
arrived: boolean = false;
private resolve: Function = null;
constructor() { this.reset(); }
reset() {
this.arrived = false;
this.greeting = new Promise<string>((resolve, reject) => { this.resolve = resolve; });
}
clicked() {
if (this.arrived) {
this.reset();
} else {
this.resolve('hi there!');
this.arrived = true;
}
}
}
// #enddocregion
// #docregion AsyncPipeObservable
@Component({
selector: 'async-observable-pipe',
template: '<div><code>observable|async</code>: Time: {{ time | async }}</div>'
})
export class AsyncObservablePipeComponent {
time = new Observable<string>((observer: Subscriber<string>) => {
setInterval(() => observer.next(new Date().toString()), 1000);
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});
}
// #enddocregion
// For some reason protractor hangs on setInterval. So we will run outside of angular zone so that
// protractor will not see us. Also we want to have this outside the docregion so as not to confuse
// the reader.
function setInterval(fn: Function, delay: number) {
const zone = Zone.current;
let rootZone = zone;
while (rootZone.parent) {
rootZone = rootZone.parent;
}
rootZone.run(
() => { window.setInterval(function() { zone.run(fn, this, arguments as any); }, delay); });
}