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119 lines
4.3 KiB
119 lines
4.3 KiB
"use strict"; |
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var __extends = (this && this.__extends) || function (d, b) { |
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for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p]; |
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function __() { this.constructor = d; } |
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d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __()); |
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}; |
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var Subscriber_1 = require('../Subscriber'); |
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var EmptyError_1 = require('../util/EmptyError'); |
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/* tslint:enable:max-line-length */ |
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/** |
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* Returns an Observable that emits only the last item emitted by the source Observable. |
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* It optionally takes a predicate function as a parameter, in which case, rather than emitting |
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* the last item from the source Observable, the resulting Observable will emit the last item |
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* from the source Observable that satisfies the predicate. |
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* |
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* <img src="./img/last.png" width="100%"> |
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* |
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* @throws {EmptyError} Delivers an EmptyError to the Observer's `error` |
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* callback if the Observable completes before any `next` notification was sent. |
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* @param {function} predicate - The condition any source emitted item has to satisfy. |
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* @return {Observable} An Observable that emits only the last item satisfying the given condition |
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* from the source, or an NoSuchElementException if no such items are emitted. |
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* @throws - Throws if no items that match the predicate are emitted by the source Observable. |
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* @method last |
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* @owner Observable |
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*/ |
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function last(predicate, resultSelector, defaultValue) { |
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return function (source) { return source.lift(new LastOperator(predicate, resultSelector, defaultValue, source)); }; |
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} |
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exports.last = last; |
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var LastOperator = (function () { |
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function LastOperator(predicate, resultSelector, defaultValue, source) { |
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this.predicate = predicate; |
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this.resultSelector = resultSelector; |
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this.defaultValue = defaultValue; |
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this.source = source; |
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} |
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LastOperator.prototype.call = function (observer, source) { |
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return source.subscribe(new LastSubscriber(observer, this.predicate, this.resultSelector, this.defaultValue, this.source)); |
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}; |
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return LastOperator; |
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}()); |
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/** |
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* We need this JSDoc comment for affecting ESDoc. |
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* @ignore |
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* @extends {Ignored} |
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*/ |
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var LastSubscriber = (function (_super) { |
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__extends(LastSubscriber, _super); |
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function LastSubscriber(destination, predicate, resultSelector, defaultValue, source) { |
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_super.call(this, destination); |
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this.predicate = predicate; |
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this.resultSelector = resultSelector; |
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this.defaultValue = defaultValue; |
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this.source = source; |
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this.hasValue = false; |
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this.index = 0; |
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if (typeof defaultValue !== 'undefined') { |
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this.lastValue = defaultValue; |
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this.hasValue = true; |
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} |
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} |
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LastSubscriber.prototype._next = function (value) { |
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var index = this.index++; |
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if (this.predicate) { |
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this._tryPredicate(value, index); |
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} |
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else { |
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if (this.resultSelector) { |
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this._tryResultSelector(value, index); |
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return; |
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} |
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this.lastValue = value; |
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this.hasValue = true; |
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} |
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}; |
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LastSubscriber.prototype._tryPredicate = function (value, index) { |
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var result; |
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try { |
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result = this.predicate(value, index, this.source); |
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} |
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catch (err) { |
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this.destination.error(err); |
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return; |
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} |
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if (result) { |
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if (this.resultSelector) { |
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this._tryResultSelector(value, index); |
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return; |
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} |
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this.lastValue = value; |
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this.hasValue = true; |
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} |
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}; |
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LastSubscriber.prototype._tryResultSelector = function (value, index) { |
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var result; |
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try { |
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result = this.resultSelector(value, index); |
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} |
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catch (err) { |
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this.destination.error(err); |
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return; |
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} |
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this.lastValue = result; |
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this.hasValue = true; |
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}; |
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LastSubscriber.prototype._complete = function () { |
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var destination = this.destination; |
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if (this.hasValue) { |
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destination.next(this.lastValue); |
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destination.complete(); |
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} |
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else { |
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destination.error(new EmptyError_1.EmptyError); |
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} |
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}; |
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return LastSubscriber; |
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}(Subscriber_1.Subscriber)); |
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//# sourceMappingURL=last.js.map
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