1  var copyObject = require('./_copyObject'),
 2      createAssigner = require('./_createAssigner'),
 3      keys = require('./keys');
 4  
 5  /**
 6   * This method is like `_.assign` except that it accepts `customizer`
 7   * which is invoked to produce the assigned values. If `customizer` returns
 8   * `undefined`, assignment is handled by the method instead. The `customizer`
 9   * is invoked with five arguments: (objValue, srcValue, key, object, source).
10   *
11   * **Note:** This method mutates `object`.
12   *
13   * @static
14   * @memberOf _
15   * @since 4.0.0
16   * @category Object
17   * @param {Object} object The destination object.
18   * @param {...Object} sources The source objects.
19   * @param {Function} [customizer] The function to customize assigned values.
20   * @returns {Object} Returns `object`.
21   * @see _.assignInWith
22   * @example
23   *
24   * function customizer(objValue, srcValue) {
25   *   return _.isUndefined(objValue) ? srcValue : objValue;
26   * }
27   *
28   * var defaults = _.partialRight(_.assignWith, customizer);
29   *
30   * defaults({ 'a': 1 }, { 'b': 2 }, { 'a': 3 });
31   * // => { 'a': 1, 'b': 2 }
32   */
33  var assignWith = createAssigner(function(object, source, srcIndex, customizer) {
34    copyObject(source, keys(source), object, customizer);
35  });
36  
37  module.exports = assignWith;