| /** 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 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 function takeLastOperatorFunction(source) { |
| if (count === 0) { |
| return new EmptyObservable(); |
| } |
| else { |
| return source.lift(new TakeLastOperator(count)); |
| } |
| }; |
| } |
| var TakeLastOperator = /*@__PURE__*/ (/*@__PURE__*/ function () { |
| function TakeLastOperator(total) { |
| this.total = total; |
| if (this.total < 0) { |
| throw new ArgumentOutOfRangeError; |
| } |
| } |
| TakeLastOperator.prototype.call = function (subscriber, source) { |
| return source.subscribe(new TakeLastSubscriber(subscriber, this.total)); |
| }; |
| return TakeLastOperator; |
| }()); |
| /** |
| * We need this JSDoc comment for affecting ESDoc. |
| * @ignore |
| * @extends {Ignored} |
| */ |
| var TakeLastSubscriber = /*@__PURE__*/ (/*@__PURE__*/ function (_super) { |
| __extends(TakeLastSubscriber, _super); |
| function TakeLastSubscriber(destination, total) { |
| _super.call(this, destination); |
| this.total = total; |
| this.ring = new Array(); |
| this.count = 0; |
| } |
| TakeLastSubscriber.prototype._next = function (value) { |
| var ring = this.ring; |
| var total = this.total; |
| var count = this.count++; |
| if (ring.length < total) { |
| ring.push(value); |
| } |
| else { |
| var index = count % total; |
| ring[index] = value; |
| } |
| }; |
| TakeLastSubscriber.prototype._complete = function () { |
| var destination = this.destination; |
| var count = this.count; |
| if (count > 0) { |
| var total = this.count >= this.total ? this.total : this.count; |
| var ring = this.ring; |
| for (var i = 0; i < total; i++) { |
| var idx = (count++) % total; |
| destination.next(ring[idx]); |
| } |
| } |
| destination.complete(); |
| }; |
| return TakeLastSubscriber; |
| }(Subscriber)); |
| //# sourceMappingURL=takeLast.js.map |