43 lines
1.8 KiB
JavaScript
43 lines
1.8 KiB
JavaScript
/** PURE_IMPORTS_START .._operators_takeLast PURE_IMPORTS_END */
|
|
import { takeLast as higherOrderTakeLast } from '../operators/takeLast';
|
|
/**
|
|
* Emits only the last `count` values emitted by the source Observable.
|
|
*
|
|
* <span class="informal">Remembers the latest `count` values, then emits those
|
|
* only when the source completes.</span>
|
|
*
|
|
* <img src="./img/takeLast.png" width="100%">
|
|
*
|
|
* `takeLast` returns an Observable that emits at most the last `count` values
|
|
* emitted by the source Observable. If the source emits fewer than `count`
|
|
* values then all of its values are emitted. This operator must wait until the
|
|
* `complete` notification emission from the source in order to emit the `next`
|
|
* values on the output Observable, because otherwise it is impossible to know
|
|
* whether or not more values will be emitted on the source. For this reason,
|
|
* all values are emitted synchronously, followed by the complete notification.
|
|
*
|
|
* @example <caption>Take the last 3 values of an Observable with many values</caption>
|
|
* var many = Rx.Observable.range(1, 100);
|
|
* var lastThree = many.takeLast(3);
|
|
* lastThree.subscribe(x => console.log(x));
|
|
*
|
|
* @see {@link take}
|
|
* @see {@link takeUntil}
|
|
* @see {@link takeWhile}
|
|
* @see {@link skip}
|
|
*
|
|
* @throws {ArgumentOutOfRangeError} When using `takeLast(i)`, it delivers an
|
|
* ArgumentOutOrRangeError to the Observer's `error` callback if `i < 0`.
|
|
*
|
|
* @param {number} count The maximum number of values to emit from the end of
|
|
* the sequence of values emitted by the source Observable.
|
|
* @return {Observable<T>} An Observable that emits at most the last count
|
|
* values emitted by the source Observable.
|
|
* @method takeLast
|
|
* @owner Observable
|
|
*/
|
|
export function takeLast(count) {
|
|
return higherOrderTakeLast(count)(this);
|
|
}
|
|
//# sourceMappingURL=takeLast.js.map
|