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- import { OperatorFunction } from '../types';
- /**
- * Emits `false` if the input Observable emits any values, or emits `true` if the
- * input Observable completes without emitting any values.
- *
- * <span class="informal">Tells whether any values are emitted by an Observable.</span>
- *
- * 
- *
- * `isEmpty` transforms an Observable that emits values into an Observable that
- * emits a single boolean value representing whether or not any values were
- * emitted by the source Observable. As soon as the source Observable emits a
- * value, `isEmpty` will emit a `false` and complete. If the source Observable
- * completes having not emitted anything, `isEmpty` will emit a `true` and
- * complete.
- *
- * A similar effect could be achieved with {@link count}, but `isEmpty` can emit
- * a `false` value sooner.
- *
- * ## Examples
- *
- * Emit `false` for a non-empty Observable
- *
- * ```ts
- * import { Subject, isEmpty } from 'rxjs';
- *
- * const source = new Subject<string>();
- * const result = source.pipe(isEmpty());
- *
- * source.subscribe(x => console.log(x));
- * result.subscribe(x => console.log(x));
- *
- * source.next('a');
- * source.next('b');
- * source.next('c');
- * source.complete();
- *
- * // Outputs
- * // 'a'
- * // false
- * // 'b'
- * // 'c'
- * ```
- *
- * Emit `true` for an empty Observable
- *
- * ```ts
- * import { EMPTY, isEmpty } from 'rxjs';
- *
- * const result = EMPTY.pipe(isEmpty());
- * result.subscribe(x => console.log(x));
- *
- * // Outputs
- * // true
- * ```
- *
- * @see {@link count}
- * @see {@link EMPTY}
- *
- * @return A function that returns an Observable that emits boolean value
- * indicating whether the source Observable was empty or not.
- */
- export declare function isEmpty<T>(): OperatorFunction<T, boolean>;
- //# sourceMappingURL=isEmpty.d.ts.map
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