93 lines
3.2 KiB
JavaScript
93 lines
3.2 KiB
JavaScript
|
/** PURE_IMPORTS_START .._Subscriber,.._util_ArgumentOutOfRangeError,.._observable_EmptyObservable PURE_IMPORTS_END */
|
||
|
|
var __extends = (this && this.__extends) || function (d, b) {
|
||
|
|
for (var p in b)
|
||
|
|
if (b.hasOwnProperty(p))
|
||
|
|
d[p] = b[p];
|
||
|
|
function __() { this.constructor = d; }
|
||
|
|
d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
|
||
|
|
};
|
||
|
|
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 function (source) {
|
||
|
|
if (count === 0) {
|
||
|
|
return new EmptyObservable();
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
return source.lift(new TakeOperator(count));
|
||
|
|
}
|
||
|
|
};
|
||
|
|
}
|
||
|
|
var TakeOperator = /*@__PURE__*/ (/*@__PURE__*/ function () {
|
||
|
|
function TakeOperator(total) {
|
||
|
|
this.total = total;
|
||
|
|
if (this.total < 0) {
|
||
|
|
throw new ArgumentOutOfRangeError;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
TakeOperator.prototype.call = function (subscriber, source) {
|
||
|
|
return source.subscribe(new TakeSubscriber(subscriber, this.total));
|
||
|
|
};
|
||
|
|
return TakeOperator;
|
||
|
|
}());
|
||
|
|
/**
|
||
|
|
* We need this JSDoc comment for affecting ESDoc.
|
||
|
|
* @ignore
|
||
|
|
* @extends {Ignored}
|
||
|
|
*/
|
||
|
|
var TakeSubscriber = /*@__PURE__*/ (/*@__PURE__*/ function (_super) {
|
||
|
|
__extends(TakeSubscriber, _super);
|
||
|
|
function TakeSubscriber(destination, total) {
|
||
|
|
_super.call(this, destination);
|
||
|
|
this.total = total;
|
||
|
|
this.count = 0;
|
||
|
|
}
|
||
|
|
TakeSubscriber.prototype._next = function (value) {
|
||
|
|
var total = this.total;
|
||
|
|
var count = ++this.count;
|
||
|
|
if (count <= total) {
|
||
|
|
this.destination.next(value);
|
||
|
|
if (count === total) {
|
||
|
|
this.destination.complete();
|
||
|
|
this.unsubscribe();
|
||
|
|
}
|
||
|
|
}
|
||
|
|
};
|
||
|
|
return TakeSubscriber;
|
||
|
|
}(Subscriber));
|
||
|
|
//# sourceMappingURL=take.js.map
|