import { OperatorFunction } from 'rxjs';
export type DeriveLoadingOptions = {
    /**
     * The time in milliseconds to wait before emiting the loading flag = true.
     */
    threshold?: number;
    /**
     * The time in milliseconds to wait before emiting the loading flag = false.
     */
    loadingTime?: number;
};
/**
 * Derive a loading state from the source observable.
 *
 * It will emit a loading flag in a "non-flickering" way. This means
 * if the async operation finishes before the threshold time, the loading flag will not change
 * to "true", it will stay false.
 *
 * It will only emit "true" when the async operation takes longer than the threshold time.
 * It will change back to "false" after at least the defined threshold + loadingTime has passed.
 * If the async operation takes longer than threshold + loadingtime, "false" will be emitted after the operation
 * has finished.
 *
 * @param options - The options to configure the loading state derivation.
 * @returns A observable that emits the loading flag.
 *
 * @param options
 */
export declare function deriveLoading<T>(options?: DeriveLoadingOptions): OperatorFunction<T, boolean>;