declare function deepmerge<T>(x: Partial<T>, y: Partial<T>, options?: deepmerge.Options): T; declare function deepmerge<T1, T2>(x: Partial<T1>, y: Partial<T2>, options?: deepmerge.Options): T1 & T2; declare namespace deepmerge { export interface Options { arrayMerge?(target: any[], source: any[], options?: Options): any[]; clone?: boolean; customMerge?: (key: string, options?: Options) => ((x: any, y: any) => any) | undefined; isMergeableObject?(value: object): boolean; } export function all (objects: object[], options?: Options): object; export function all<T> (objects: Partial<T>[], options?: Options): T; } export = deepmerge;