Opal-Estate-Pro/node_modules/rxjs/_esm2015/observable/NeverObservable.js
2019-09-13 11:27:52 +07:00

50 lines
1.6 KiB
JavaScript
Executable File

import { Observable } from '../Observable';
import { noop } from '../util/noop';
/**
* We need this JSDoc comment for affecting ESDoc.
* @extends {Ignored}
* @hide true
*/
export class NeverObservable extends Observable {
constructor() {
super();
}
/**
* Creates an Observable that emits no items to the Observer.
*
* <span class="informal">An Observable that never emits anything.</span>
*
* <img src="./img/never.png" width="100%">
*
* This static operator is useful for creating a simple Observable that emits
* neither values nor errors nor the completion notification. It can be used
* for testing purposes or for composing with other Observables. Please note
* that by never emitting a complete notification, this Observable keeps the
* subscription from being disposed automatically. Subscriptions need to be
* manually disposed.
*
* @example <caption>Emit the number 7, then never emit anything else (not even complete).</caption>
* function info() {
* console.log('Will not be called');
* }
* var result = Rx.Observable.never().startWith(7);
* result.subscribe(x => console.log(x), info, info);
*
* @see {@link create}
* @see {@link empty}
* @see {@link of}
* @see {@link throw}
*
* @return {Observable} A "never" Observable: never emits anything.
* @static true
* @name never
* @owner Observable
*/
static create() {
return new NeverObservable();
}
/** @deprecated internal use only */ _subscribe(subscriber) {
noop();
}
}
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