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Diffstat (limited to 'node_modules/rxjs/src/internal/observable/empty.ts')
| -rw-r--r-- | node_modules/rxjs/src/internal/observable/empty.ts | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/node_modules/rxjs/src/internal/observable/empty.ts b/node_modules/rxjs/src/internal/observable/empty.ts new file mode 100644 index 0000000..8f59e45 --- /dev/null +++ b/node_modules/rxjs/src/internal/observable/empty.ts @@ -0,0 +1,79 @@ +import { Observable } from '../Observable'; +import { SchedulerLike } from '../types'; + +/** + * A simple Observable that emits no items to the Observer and immediately + * emits a complete notification. + * + * <span class="informal">Just emits 'complete', and nothing else.</span> + * + *  + * + * A simple Observable that only emits the complete notification. It can be used + * for composing with other Observables, such as in a {@link mergeMap}. + * + * ## Examples + * + * Log complete notification + * + * ```ts + * import { EMPTY } from 'rxjs'; + * + * EMPTY.subscribe({ + * next: () => console.log('Next'), + * complete: () => console.log('Complete!') + * }); + * + * // Outputs + * // Complete! + * ``` + * + * Emit the number 7, then complete + * + * ```ts + * import { EMPTY, startWith } from 'rxjs'; + * + * const result = EMPTY.pipe(startWith(7)); + * result.subscribe(x => console.log(x)); + * + * // Outputs + * // 7 + * ``` + * + * Map and flatten only odd numbers to the sequence `'a'`, `'b'`, `'c'` + * + * ```ts + * import { interval, mergeMap, of, EMPTY } from 'rxjs'; + * + * const interval$ = interval(1000); + * const result = interval$.pipe( + * mergeMap(x => x % 2 === 1 ? of('a', 'b', 'c') : EMPTY), + * ); + * result.subscribe(x => console.log(x)); + * + * // Results in the following to the console: + * // x is equal to the count on the interval, e.g. (0, 1, 2, 3, ...) + * // x will occur every 1000ms + * // if x % 2 is equal to 1, print a, b, c (each on its own) + * // if x % 2 is not equal to 1, nothing will be output + * ``` + * + * @see {@link Observable} + * @see {@link NEVER} + * @see {@link of} + * @see {@link throwError} + */ +export const EMPTY = new Observable<never>((subscriber) => subscriber.complete()); + +/** + * @param scheduler A {@link SchedulerLike} to use for scheduling + * the emission of the complete notification. + * @deprecated Replaced with the {@link EMPTY} constant or {@link scheduled} (e.g. `scheduled([], scheduler)`). Will be removed in v8. + */ +export function empty(scheduler?: SchedulerLike) { + return scheduler ? emptyScheduled(scheduler) : EMPTY; +} + +function emptyScheduled(scheduler: SchedulerLike) { + return new Observable<never>((subscriber) => scheduler.schedule(() => subscriber.complete())); +} |
