export declare function reduce<T>(source: Iterable<T>, accumulator: (acc: T, value: T, index: number) => T, seed?: T): T;
export declare function reduce<T>(source: Iterable<T>, accumulator: (acc: T[], value: T, index: number) => T[], seed?: T[]): T[];
export declare function reduce<T, R>(source: Iterable<T>, accumulator: (acc: R, value: T, index: number) => R, seed?: R): R;