/**
 * Iterates the sequence and invokes the given action for each value in the sequence.
 * @param {Iterable<T>} source Source sequence.
 * @param {function:(value: T, index: number): void} callback Action to invoke for each element.
 * @param {Object} [thisArg] Optional "this" binding for the callback.
 */
export declare function forEach<TSource>(source: Iterable<TSource>, callback: (value: TSource, index: number) => void, thisArg?: any): void;