/**
 * Deeply merges multiple objects into a target object.
 * @param {T} target - The target object to merge into.
 * @param {...Partial<S>[]} sources - The source objects to merge from.
 * @returns The merged object.
 * @example
 * const obj1 = { a: { b: 2 }, c: 3 };
 * const obj2 = { a: { d: 4 }, e: 5 };
 * const merged = mergeDeep(obj1, obj2);
 * // { a: { b: 2, d: 4 }, c: 3, e: 5 }
 */
export declare function mergeDeep<T extends Record<string, any>, S extends Record<string, any>[]>(target: T, ...sources: Partial<S>): T;