81 lines
3.0 KiB
JavaScript
Executable File
81 lines
3.0 KiB
JavaScript
Executable File
/** PURE_IMPORTS_START .._Subscriber PURE_IMPORTS_END */
|
|
var __extends = (this && this.__extends) || function (d, b) {
|
|
for (var p in b)
|
|
if (b.hasOwnProperty(p))
|
|
d[p] = b[p];
|
|
function __() { this.constructor = d; }
|
|
d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
|
|
};
|
|
import { Subscriber } from '../Subscriber';
|
|
/* 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(defaultValue) {
|
|
if (defaultValue === void 0) {
|
|
defaultValue = null;
|
|
}
|
|
return function (source) { return source.lift(new DefaultIfEmptyOperator(defaultValue)); };
|
|
}
|
|
var DefaultIfEmptyOperator = /*@__PURE__*/ (/*@__PURE__*/ function () {
|
|
function DefaultIfEmptyOperator(defaultValue) {
|
|
this.defaultValue = defaultValue;
|
|
}
|
|
DefaultIfEmptyOperator.prototype.call = function (subscriber, source) {
|
|
return source.subscribe(new DefaultIfEmptySubscriber(subscriber, this.defaultValue));
|
|
};
|
|
return DefaultIfEmptyOperator;
|
|
}());
|
|
/**
|
|
* We need this JSDoc comment for affecting ESDoc.
|
|
* @ignore
|
|
* @extends {Ignored}
|
|
*/
|
|
var DefaultIfEmptySubscriber = /*@__PURE__*/ (/*@__PURE__*/ function (_super) {
|
|
__extends(DefaultIfEmptySubscriber, _super);
|
|
function DefaultIfEmptySubscriber(destination, defaultValue) {
|
|
_super.call(this, destination);
|
|
this.defaultValue = defaultValue;
|
|
this.isEmpty = true;
|
|
}
|
|
DefaultIfEmptySubscriber.prototype._next = function (value) {
|
|
this.isEmpty = false;
|
|
this.destination.next(value);
|
|
};
|
|
DefaultIfEmptySubscriber.prototype._complete = function () {
|
|
if (this.isEmpty) {
|
|
this.destination.next(this.defaultValue);
|
|
}
|
|
this.destination.complete();
|
|
};
|
|
return DefaultIfEmptySubscriber;
|
|
}(Subscriber));
|
|
//# sourceMappingURL=defaultIfEmpty.js.map
|