1var assignValue = require('./_assignValue'),
2    baseAssignValue = require('./_baseAssignValue');
3
4/**
5 * Copies properties of `source` to `object`.
6 *
7 * @private
8 * @param {Object} source The object to copy properties from.
9 * @param {Array} props The property identifiers to copy.
10 * @param {Object} [object={}] The object to copy properties to.
11 * @param {Function} [customizer] The function to customize copied values.
12 * @returns {Object} Returns `object`.
13 */
14function copyObject(source, props, object, customizer) {
15  var isNew = !object;
16  object || (object = {});
17
18  var index = -1,
19      length = props.length;
20
21  while (++index < length) {
22    var key = props[index];
23
24    var newValue = customizer
25      ? customizer(object[key], source[key], key, object, source)
26      : undefined;
27
28    if (newValue === undefined) {
29      newValue = source[key];
30    }
31    if (isNew) {
32      baseAssignValue(object, key, newValue);
33    } else {
34      assignValue(object, key, newValue);
35    }
36  }
37  return object;
38}
39
40module.exports = copyObject;
41