39 lines
1.6 KiB
JavaScript
Executable File
39 lines
1.6 KiB
JavaScript
Executable File
"use strict";
|
|
var defaultIfEmpty_1 = require('../operators/defaultIfEmpty');
|
|
/* 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
|
|
*/
|
|
function defaultIfEmpty(defaultValue) {
|
|
if (defaultValue === void 0) { defaultValue = null; }
|
|
return defaultIfEmpty_1.defaultIfEmpty(defaultValue)(this);
|
|
}
|
|
exports.defaultIfEmpty = defaultIfEmpty;
|
|
//# sourceMappingURL=defaultIfEmpty.js.map
|