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- import { Subscriber } from '../Subscriber';
- import { ArgumentOutOfRangeError } from '../util/ArgumentOutOfRangeError';
- import { EmptyObservable } from '../observable/EmptyObservable';
- /**
- * Emits only the first `count` values emitted by the source Observable.
- *
- * <span class="informal">Takes the first `count` values from the source, then
- * completes.</span>
- *
- * <img src="./img/take.png" width="100%">
- *
- * `take` returns an Observable that emits only the first `count` values emitted
- * by the source Observable. If the source emits fewer than `count` values then
- * all of its values are emitted. After that, it completes, regardless if the
- * source completes.
- *
- * @example <caption>Take the first 5 seconds of an infinite 1-second interval Observable</caption>
- * var interval = Rx.Observable.interval(1000);
- * var five = interval.take(5);
- * five.subscribe(x => console.log(x));
- *
- * @see {@link takeLast}
- * @see {@link takeUntil}
- * @see {@link takeWhile}
- * @see {@link skip}
- *
- * @throws {ArgumentOutOfRangeError} When using `take(i)`, it delivers an
- * ArgumentOutOrRangeError to the Observer's `error` callback if `i < 0`.
- *
- * @param {number} count The maximum number of `next` values to emit.
- * @return {Observable<T>} An Observable that emits only the first `count`
- * values emitted by the source Observable, or all of the values from the source
- * if the source emits fewer than `count` values.
- * @method take
- * @owner Observable
- */
- export function take(count) {
- return (source) => {
- if (count === 0) {
- return new EmptyObservable();
- }
- else {
- return source.lift(new TakeOperator(count));
- }
- };
- }
- class TakeOperator {
- constructor(total) {
- this.total = total;
- if (this.total < 0) {
- throw new ArgumentOutOfRangeError;
- }
- }
- call(subscriber, source) {
- return source.subscribe(new TakeSubscriber(subscriber, this.total));
- }
- }
- /**
- * We need this JSDoc comment for affecting ESDoc.
- * @ignore
- * @extends {Ignored}
- */
- class TakeSubscriber extends Subscriber {
- constructor(destination, total) {
- super(destination);
- this.total = total;
- this.count = 0;
- }
- _next(value) {
- const total = this.total;
- const count = ++this.count;
- if (count <= total) {
- this.destination.next(value);
- if (count === total) {
- this.destination.complete();
- this.unsubscribe();
- }
- }
- }
- }
- //# sourceMappingURL=take.js.map
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