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100 lines
3.8 KiB
100 lines
3.8 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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/** |
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* Emits only the first value emitted by the source Observable that meets some |
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* condition. |
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* |
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* <span class="informal">Finds the first value that passes some test and emits |
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* that.</span> |
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* |
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* <img src="./img/find.png" width="100%"> |
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* |
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* `find` searches for the first item in the source Observable that matches the |
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* specified condition embodied by the `predicate`, and returns the first |
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* occurrence in the source. Unlike {@link first}, the `predicate` is required |
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* in `find`, and does not emit an error if a valid value is not found. |
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* |
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* @example <caption>Find and emit the first click that happens on a DIV element</caption> |
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* var clicks = Rx.Observable.fromEvent(document, 'click'); |
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* var result = clicks.find(ev => ev.target.tagName === 'DIV'); |
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* result.subscribe(x => console.log(x)); |
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* |
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* @see {@link filter} |
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* @see {@link first} |
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* @see {@link findIndex} |
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* @see {@link take} |
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* |
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* @param {function(value: T, index: number, source: Observable<T>): boolean} predicate |
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* A function called with each item to test for condition matching. |
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* @param {any} [thisArg] An optional argument to determine the value of `this` |
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* in the `predicate` function. |
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* @return {Observable<T>} An Observable of the first item that matches the |
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* condition. |
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* @method find |
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* @owner Observable |
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*/ |
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function find(predicate, thisArg) { |
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if (typeof predicate !== 'function') { |
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throw new TypeError('predicate is not a function'); |
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} |
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return function (source) { return source.lift(new FindValueOperator(predicate, source, false, thisArg)); }; |
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} |
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exports.find = find; |
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var FindValueOperator = (function () { |
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function FindValueOperator(predicate, source, yieldIndex, thisArg) { |
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this.predicate = predicate; |
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this.source = source; |
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this.yieldIndex = yieldIndex; |
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this.thisArg = thisArg; |
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} |
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FindValueOperator.prototype.call = function (observer, source) { |
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return source.subscribe(new FindValueSubscriber(observer, this.predicate, this.source, this.yieldIndex, this.thisArg)); |
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}; |
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return FindValueOperator; |
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}()); |
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exports.FindValueOperator = FindValueOperator; |
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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 FindValueSubscriber = (function (_super) { |
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__extends(FindValueSubscriber, _super); |
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function FindValueSubscriber(destination, predicate, source, yieldIndex, thisArg) { |
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_super.call(this, destination); |
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this.predicate = predicate; |
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this.source = source; |
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this.yieldIndex = yieldIndex; |
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this.thisArg = thisArg; |
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this.index = 0; |
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} |
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FindValueSubscriber.prototype.notifyComplete = function (value) { |
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var destination = this.destination; |
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destination.next(value); |
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destination.complete(); |
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}; |
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FindValueSubscriber.prototype._next = function (value) { |
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var _a = this, predicate = _a.predicate, thisArg = _a.thisArg; |
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var index = this.index++; |
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try { |
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var result = predicate.call(thisArg || this, value, index, this.source); |
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if (result) { |
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this.notifyComplete(this.yieldIndex ? index : value); |
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} |
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} |
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catch (err) { |
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this.destination.error(err); |
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} |
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}; |
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FindValueSubscriber.prototype._complete = function () { |
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this.notifyComplete(this.yieldIndex ? -1 : undefined); |
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}; |
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return FindValueSubscriber; |
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}(Subscriber_1.Subscriber)); |
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exports.FindValueSubscriber = FindValueSubscriber; |
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//# sourceMappingURL=find.js.map
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