/**
 * Reads through a Generator, awaiting `cb` on each element.
 * If the returned result is truthy, that result is emitted. Otherwise, nothing is emitted.
 */
export declare function filterMap<T, TR, R>(gen: AsyncGenerator<T, TR>, cb: (ele: T) => R): AsyncGenerator<NonNullable<R>, number, unknown>;
/**
 * Iterates a Generator, and runs the given callback for each element.
 * @returns The total count of elements iterated.
 */
export declare function forGen<T>(gen: AsyncGenerator<T>, cb: (ele: T, idx: number, stop: Function) => void): Promise<number>;