1function override(source1, source2) {
2  var target = {};
3  var key1;
4  var key2;
5  var item;
6
7  for (key1 in source1) {
8    item = source1[key1];
9
10    if (Array.isArray(item)) {
11      target[key1] = item.slice(0);
12    } else if (typeof item == 'object' && item !== null) {
13      target[key1] = override(item, {});
14    } else {
15      target[key1] = item;
16    }
17  }
18
19  for (key2 in source2) {
20    item = source2[key2];
21
22    if (key2 in target && Array.isArray(item)) {
23      target[key2] = item.slice(0);
24    } else if (key2 in target && typeof item == 'object' && item !== null) {
25      target[key2] = override(target[key2], item);
26    } else {
27      target[key2] = item;
28    }
29  }
30
31  return target;
32}
33
34module.exports = override;
35