Sha256: f554bba80ac8313af284d15ebe5ae6abc914cbe2ea5a67a923b3bd7b9a0548c6
Contents?: true
Size: 1.72 KB
Versions: 49
Compression:
Stored size: 1.72 KB
Contents
import { Observable } from '../Observable';
import { defaultIfEmpty as higherOrder } from '../operators/defaultIfEmpty';
/* tslint:disable:max-line-length */
export function defaultIfEmpty<T>(this: Observable<T>, defaultValue?: T): Observable<T>;
export function defaultIfEmpty<T, R>(this: Observable<T>, defaultValue?: R): Observable<T | R>;
/* tslint:enable:max-line-length */
/**
* Emits a given value if the source Observable completes without emitting any
* `next` value, otherwise mirrors the source Observable.
*
* <span class="informal">If the source Observable turns out to be empty, then
* this operator will emit a default value.</span>
*
* <img src="./img/defaultIfEmpty.png" width="100%">
*
* `defaultIfEmpty` emits the values emitted by the source Observable or a
* specified default value if the source Observable is empty (completes without
* having emitted any `next` value).
*
* @example <caption>If no clicks happen in 5 seconds, then emit "no clicks"</caption>
* var clicks = Rx.Observable.fromEvent(document, 'click');
* var clicksBeforeFive = clicks.takeUntil(Rx.Observable.interval(5000));
* var result = clicksBeforeFive.defaultIfEmpty('no clicks');
* result.subscribe(x => console.log(x));
*
* @see {@link empty}
* @see {@link last}
*
* @param {any} [defaultValue=null] The default value used if the source
* Observable is empty.
* @return {Observable} An Observable that emits either the specified
* `defaultValue` if the source Observable emits no items, or the values emitted
* by the source Observable.
* @method defaultIfEmpty
* @owner Observable
*/
export function defaultIfEmpty<T, R>(this: Observable<T>, defaultValue: R = null): Observable<T | R> {
return higherOrder<T, R>(defaultValue)(this);
}
Version data entries
49 entries across 49 versions & 4 rubygems