86 lines
3.0 KiB
JavaScript
86 lines
3.0 KiB
JavaScript
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"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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/**
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* Returns an Observable that emits the single item emitted by the source Observable that matches a specified
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* predicate, if that Observable emits one such item. If the source Observable emits more than one such item or no
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* such items, notify of an IllegalArgumentException or NoSuchElementException respectively.
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*
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* <img src="./img/single.png" width="100%">
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*
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* @param {Function} a predicate function to evaluate items emitted by the source Observable.
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* @returns {Observable<T>} an Observable that emits the single item emitted by the source Observable that matches
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* the predicate.
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.
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*/
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function single(predicate) {
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return this.lift(new SingleOperator(predicate, this));
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}
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exports.single = single;
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var SingleOperator = (function () {
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function SingleOperator(predicate, source) {
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this.predicate = predicate;
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this.source = source;
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}
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SingleOperator.prototype.call = function (subscriber) {
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return new SingleSubscriber(subscriber, this.predicate, this.source);
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};
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return SingleOperator;
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}());
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var SingleSubscriber = (function (_super) {
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__extends(SingleSubscriber, _super);
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function SingleSubscriber(destination, predicate, source) {
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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.seenValue = false;
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this.index = 0;
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}
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SingleSubscriber.prototype.applySingleValue = function (value) {
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if (this.seenValue) {
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this.destination.error('Sequence contains more than one element');
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}
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else {
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this.seenValue = true;
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this.singleValue = value;
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}
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};
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SingleSubscriber.prototype._next = function (value) {
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var predicate = this.predicate;
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this.index++;
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if (predicate) {
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this.tryNext(value);
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}
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else {
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this.applySingleValue(value);
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}
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};
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SingleSubscriber.prototype.tryNext = function (value) {
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try {
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var result = this.predicate(value, this.index, this.source);
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if (result) {
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this.applySingleValue(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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SingleSubscriber.prototype._complete = function () {
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var destination = this.destination;
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if (this.index > 0) {
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destination.next(this.seenValue ? this.singleValue : undefined);
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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 SingleSubscriber;
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}(Subscriber_1.Subscriber));
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//# sourceMappingURL=single.js.map
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