import type { UmbDeepPartialObject } from '../type/deep-partial-object.type.js';
/**
 * Deep merge two objects.
 * @template {{ [key: string]: unknown }} T
 * @template {UmbDeepPartialObject<T>} PartialType
 * @param {PartialType} source - The partial object to merge into the fallback.
 * @param {T} fallback - The object providing the default values.
 * @returns {T} The merged object.
 */
export declare function umbDeepMerge<T extends {
    [key: string]: any;
}, PartialType extends UmbDeepPartialObject<T> = UmbDeepPartialObject<T>>(source: PartialType, fallback: T): T;