| /** PURE_IMPORTS_START .._operators_defaultIfEmpty PURE_IMPORTS_END */ |
| import { defaultIfEmpty as higherOrder } from '../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 |
| */ |
| export function defaultIfEmpty(defaultValue) { |
| if (defaultValue === void 0) { |
| defaultValue = null; |
| } |
| return higherOrder(defaultValue)(this); |
| } |
| //# sourceMappingURL=defaultIfEmpty.js.map |
