import type { Observable } from './types/outputs/Observable.js';
import type { StrictObserver } from './types/outputs/StrictObserver.js';
/**
 * Creates a source object, emitting any given data or error, until completion.
 *
 * @since 1.0.0
 */
export declare function source$<D>(): Source<D>;
/**
 * Observable object emitting given values.
 *
 * @since 1.0.0
 */
export interface Source<in out D = unknown> extends Observable<D>, Omit<StrictObserver<D>, 'start'> {
    /**
     * Indicates if source is completed.
     * A completed source does not emit anymore, as no subscription and refuse any new ones.
     *
     * @since 1.0.0
     */
    readonly isCompleted: boolean;
}