/**
 * Assigns own enumerable string keyed properties of source objects to the
 * destination object. Source objects are applied from left to right.
 * Subsequent sources overwrite property assignments of previous sources.
 *
 * @param object - The destination object
 * @param sources - The source objects
 * @returns The destination object
 *
 * @example
 * ```ts
 * const object = { 'a': 1 };
 *
 * assign(object, { 'b': 2 }, { 'c': 3 });
 * // => { 'a': 1, 'b': 2, 'c': 3 }
 * ```
 */
export declare function assign<T extends object, U extends object>(object: T, ...sources: U[]): T & U;
/**
 * This method is like assign except that it iterates over own and
 * inherited source properties.
 *
 * @param object - The destination object
 * @param sources - The source objects
 * @returns The destination object
 *
 * @example
 * ```ts
 * function Foo() {
 *   this.a = 1;
 * }
 *
 * Foo.prototype.b = 2;
 *
 * assignIn({ 'c': 3 }, new Foo);
 * // => { 'a': 1, 'b': 2, 'c': 3 }
 * ```
 */
export declare function assignIn<T extends object, U extends object>(object: T, ...sources: U[]): T & U;
/**
 * This method is like assign except that it accepts customizer which
 * is invoked to produce the assigned values. If customizer returns undefined,
 * assignment is handled by the method instead. The customizer is invoked
 * with five arguments: (objValue, srcValue, key, object, source).
 *
 * @param object - The destination object
 * @param sources - The source objects
 * @param customizer - The function to customize assigned values
 * @returns The destination object
 *
 * @example
 * ```ts
 * function customizer(objValue, srcValue) {
 *   return _.isUndefined(objValue) ? srcValue : objValue;
 * }
 *
 * const defaults = _.partialRight(_.assignWith, customizer);
 *
 * defaults({ 'a': 1 }, { 'b': 2 }, { 'a': 3 });
 * // => { 'a': 1, 'b': 2 }
 * ```
 */
export declare function assignWith<T extends object, U extends object>(object: T, source: U, customizer: (objValue: any, srcValue: any, key: string, object: T, source: U) => any): T & U;
/**
 * This method is like assignIn except that it accepts customizer which
 * is invoked to produce the assigned values. If customizer returns undefined,
 * assignment is handled by the method instead. The customizer is invoked
 * with five arguments: (objValue, srcValue, key, object, source).
 *
 * @param object - The destination object
 * @param sources - The source objects
 * @param customizer - The function to customize assigned values
 * @returns The destination object
 *
 * @example
 * ```ts
 * function customizer(objValue, srcValue) {
 *   return _.isUndefined(objValue) ? srcValue : objValue;
 * }
 *
 * const defaults = _.partialRight(_.assignInWith, customizer);
 *
 * defaults({ 'a': 1 }, { 'b': 2 }, { 'a': 3 });
 * // => { 'a': 1, 'b': 2 }
 * ```
 */
export declare function assignInWith<T extends object, U extends object>(object: T, source: U, customizer: (objValue: any, srcValue: any, key: string, object: T, source: U) => any): T & U;
export declare const extend: typeof assignIn;
export declare const extendWith: typeof assignInWith;