1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
|
import { Operator } from '../Operator';
import { Observable } from '../Observable';
import { Subscriber } from '../Subscriber';
import { OuterSubscriber } from '../OuterSubscriber';
import { InnerSubscriber } from '../InnerSubscriber';
import { subscribeToResult } from '../util/subscribeToResult';
import { MonoTypeOperatorFunction, TeardownLogic } from '../types';
/**
* Emits the values emitted by the source Observable until a `notifier`
* Observable emits a value.
*
* <span class="informal">Lets values pass until a second Observable,
* `notifier`, emits a value. Then, it completes.</span>
*
* 
*
* `takeUntil` subscribes and begins mirroring the source Observable. It also
* monitors a second Observable, `notifier` that you provide. If the `notifier`
* emits a value, the output Observable stops mirroring the source Observable
* and completes. If the `notifier` doesn't emit any value and completes
* then `takeUntil` will pass all values.
*
* ## Example
* Tick every second until the first click happens
* ```javascript
* import { fromEvent, interval } from 'rxjs';
* import { takeUntil } from 'rxjs/operators';
*
* const source = interval(1000);
* const clicks = fromEvent(document, 'click');
* const result = source.pipe(takeUntil(clicks));
* result.subscribe(x => console.log(x));
* ```
*
* @see {@link take}
* @see {@link takeLast}
* @see {@link takeWhile}
* @see {@link skip}
*
* @param {Observable} notifier The Observable whose first emitted value will
* cause the output Observable of `takeUntil` to stop emitting values from the
* source Observable.
* @return {Observable<T>} An Observable that emits the values from the source
* Observable until such time as `notifier` emits its first value.
* @method takeUntil
* @owner Observable
*/
export function takeUntil<T>(notifier: Observable<any>): MonoTypeOperatorFunction<T> {
return (source: Observable<T>) => source.lift(new TakeUntilOperator(notifier));
}
class TakeUntilOperator<T> implements Operator<T, T> {
constructor(private notifier: Observable<any>) {
}
call(subscriber: Subscriber<T>, source: any): TeardownLogic {
const takeUntilSubscriber = new TakeUntilSubscriber(subscriber);
const notifierSubscription = subscribeToResult(takeUntilSubscriber, this.notifier);
if (notifierSubscription && !takeUntilSubscriber.seenValue) {
takeUntilSubscriber.add(notifierSubscription);
return source.subscribe(takeUntilSubscriber);
}
return takeUntilSubscriber;
}
}
/**
* We need this JSDoc comment for affecting ESDoc.
* @ignore
* @extends {Ignored}
*/
class TakeUntilSubscriber<T, R> extends OuterSubscriber<T, R> {
seenValue = false;
constructor(destination: Subscriber<any>, ) {
super(destination);
}
notifyNext(outerValue: T, innerValue: R,
outerIndex: number, innerIndex: number,
innerSub: InnerSubscriber<T, R>): void {
this.seenValue = true;
this.complete();
}
notifyComplete(): void {
// noop
}
}
|
