60 lines
2.4 KiB
JavaScript
60 lines
2.4 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 ArgumentOutOfRangeError_1 = require('../util/ArgumentOutOfRangeError');
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/**
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* Returns an Observable that emits the item at the specified index in the source Observable.
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* If default is given, missing indices will output this value on next; otherwise, outputs error.
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* @param {number} index the index of the value to be retrieved.
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* @param {any} [defaultValue] the default value returned for missing indices.
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* @returns {Observable} an Observable that emits a single item, if it is found. Otherwise, will emit the default value if given.
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*/
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function elementAt(index, defaultValue) {
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return this.lift(new ElementAtOperator(index, defaultValue));
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}
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exports.elementAt = elementAt;
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var ElementAtOperator = (function () {
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function ElementAtOperator(index, defaultValue) {
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this.index = index;
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this.defaultValue = defaultValue;
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if (index < 0) {
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throw new ArgumentOutOfRangeError_1.ArgumentOutOfRangeError;
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}
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}
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ElementAtOperator.prototype.call = function (subscriber) {
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return new ElementAtSubscriber(subscriber, this.index, this.defaultValue);
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};
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return ElementAtOperator;
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}());
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var ElementAtSubscriber = (function (_super) {
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__extends(ElementAtSubscriber, _super);
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function ElementAtSubscriber(destination, index, defaultValue) {
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_super.call(this, destination);
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this.index = index;
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this.defaultValue = defaultValue;
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}
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ElementAtSubscriber.prototype._next = function (x) {
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if (this.index-- === 0) {
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this.destination.next(x);
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this.destination.complete();
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}
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};
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ElementAtSubscriber.prototype._complete = function () {
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var destination = this.destination;
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if (this.index >= 0) {
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if (typeof this.defaultValue !== 'undefined') {
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destination.next(this.defaultValue);
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}
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else {
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destination.error(new ArgumentOutOfRangeError_1.ArgumentOutOfRangeError);
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}
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}
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destination.complete();
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};
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return ElementAtSubscriber;
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}(Subscriber_1.Subscriber));
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//# sourceMappingURL=elementAt.js.map
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