UNPKG

@reactivex/rxjs

Version:

Reactive Extensions for modern JavaScript

42 lines 1.47 kB
import { ArrayObservable } from '../observable/ArrayObservable'; import { ScalarObservable } from '../observable/ScalarObservable'; import { EmptyObservable } from '../observable/EmptyObservable'; import { concatStatic } from './concat'; import { isScheduler } from '../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 */ export 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(scheduler)) { array.pop(); } else { scheduler = null; } var len = array.length; if (len === 1) { return concatStatic(new ScalarObservable(array[0], scheduler), this); } else if (len > 1) { return concatStatic(new ArrayObservable(array, scheduler), this); } else { return concatStatic(new EmptyObservable(scheduler), this); } } //# sourceMappingURL=startWith.js.map