startWith.js
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"use strict";
var ArrayObservable_1 = require('../observable/ArrayObservable');
var ScalarObservable_1 = require('../observable/ScalarObservable');
var EmptyObservable_1 = require('../observable/EmptyObservable');
var concat_1 = require('./concat');
var isScheduler_1 = require('../util/isScheduler');
/* tslint:disable:max-line-length */
/**
* Returns an Observable that emits the items in a specified Iterable before it begins to emit items emitted by the
* source Observable.
*
* <img src="./img/startWith.png" width="100%">
*
* @param {Values} an Iterable that contains the items you want the modified Observable to emit first.
* @return {Observable} an Observable that emits the items in the specified Iterable and then emits the items
* emitted by the source Observable.
* @method startWith
* @owner Observable
*/
function startWith() {
var array = [];
for (var _i = 0; _i < arguments.length; _i++) {
array[_i - 0] = arguments[_i];
}
var scheduler = array[array.length - 1];
if (isScheduler_1.isScheduler(scheduler)) {
array.pop();
}
else {
scheduler = null;
}
var len = array.length;
if (len === 1) {
return concat_1.concatStatic(new ScalarObservable_1.ScalarObservable(array[0], scheduler), this);
}
else if (len > 1) {
return concat_1.concatStatic(new ArrayObservable_1.ArrayObservable(array, scheduler), this);
}
else {
return concat_1.concatStatic(new EmptyObservable_1.EmptyObservable(scheduler), this);
}
}
exports.startWith = startWith;
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