work.suroh.tk/node_modules/rxjs/_esm2015/operators/timeoutWith.js

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2019-12-02 12:22:45 +00:00
import { async } from '../scheduler/async';
import { isDate } from '../util/isDate';
import { OuterSubscriber } from '../OuterSubscriber';
import { subscribeToResult } from '../util/subscribeToResult';
/* tslint:enable:max-line-length */
/**
*
* Errors if Observable does not emit a value in given time span, in case of which
* subscribes to the second Observable.
*
* <span class="informal">It's a version of `timeout` operator that let's you specify fallback Observable.</span>
*
* <img src="./img/timeoutWith.png" width="100%">
*
* `timeoutWith` is a variation of `timeout` operator. It behaves exactly the same,
* still accepting as a first argument either a number or a Date, which control - respectively -
* when values of source Observable should be emitted or when it should complete.
*
* The only difference is that it accepts a second, required parameter. This parameter
* should be an Observable which will be subscribed when source Observable fails any timeout check.
* So whenever regular `timeout` would emit an error, `timeoutWith` will instead start re-emitting
* values from second Observable. Note that this fallback Observable is not checked for timeouts
* itself, so it can emit values and complete at arbitrary points in time. From the moment of a second
* subscription, Observable returned from `timeoutWith` simply mirrors fallback stream. When that
* stream completes, it completes as well.
*
* Scheduler, which in case of `timeout` is provided as as second argument, can be still provided
* here - as a third, optional parameter. It still is used to schedule timeout checks and -
* as a consequence - when second Observable will be subscribed, since subscription happens
* immediately after failing check.
*
* @example <caption>Add fallback observable</caption>
* const seconds = Rx.Observable.interval(1000);
* const minutes = Rx.Observable.interval(60 * 1000);
*
* seconds.timeoutWith(900, minutes)
* .subscribe(
* value => console.log(value), // After 900ms, will start emitting `minutes`,
* // since first value of `seconds` will not arrive fast enough.
* err => console.log(err) // Would be called after 900ms in case of `timeout`,
* // but here will never be called.
* );
*
* @param {number|Date} due Number specifying period within which Observable must emit values
* or Date specifying before when Observable should complete
* @param {Observable<T>} withObservable Observable which will be subscribed if source fails timeout check.
* @param {Scheduler} [scheduler] Scheduler controlling when timeout checks occur.
* @return {Observable<T>} Observable that mirrors behaviour of source or, when timeout check fails, of an Observable
* passed as a second parameter.
* @method timeoutWith
* @owner Observable
*/
export function timeoutWith(due, withObservable, scheduler = async) {
return (source) => {
let absoluteTimeout = isDate(due);
let waitFor = absoluteTimeout ? (+due - scheduler.now()) : Math.abs(due);
return source.lift(new TimeoutWithOperator(waitFor, absoluteTimeout, withObservable, scheduler));
};
}
class TimeoutWithOperator {
constructor(waitFor, absoluteTimeout, withObservable, scheduler) {
this.waitFor = waitFor;
this.absoluteTimeout = absoluteTimeout;
this.withObservable = withObservable;
this.scheduler = scheduler;
}
call(subscriber, source) {
return source.subscribe(new TimeoutWithSubscriber(subscriber, this.absoluteTimeout, this.waitFor, this.withObservable, this.scheduler));
}
}
/**
* We need this JSDoc comment for affecting ESDoc.
* @ignore
* @extends {Ignored}
*/
class TimeoutWithSubscriber extends OuterSubscriber {
constructor(destination, absoluteTimeout, waitFor, withObservable, scheduler) {
super(destination);
this.absoluteTimeout = absoluteTimeout;
this.waitFor = waitFor;
this.withObservable = withObservable;
this.scheduler = scheduler;
this.action = null;
this.scheduleTimeout();
}
static dispatchTimeout(subscriber) {
const { withObservable } = subscriber;
subscriber._unsubscribeAndRecycle();
subscriber.add(subscribeToResult(subscriber, withObservable));
}
scheduleTimeout() {
const { action } = this;
if (action) {
// Recycle the action if we've already scheduled one. All the production
// Scheduler Actions mutate their state/delay time and return themeselves.
// VirtualActions are immutable, so they create and return a clone. In this
// case, we need to set the action reference to the most recent VirtualAction,
// to ensure that's the one we clone from next time.
this.action = action.schedule(this, this.waitFor);
}
else {
this.add(this.action = this.scheduler.schedule(TimeoutWithSubscriber.dispatchTimeout, this.waitFor, this));
}
}
_next(value) {
if (!this.absoluteTimeout) {
this.scheduleTimeout();
}
super._next(value);
}
/** @deprecated internal use only */ _unsubscribe() {
this.action = null;
this.scheduler = null;
this.withObservable = null;
}
}
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