var list = new List();
l.insert(1);
l.insert(2);
l.insert(3);
Maybe this example is contrived, but I feel like it is much more of a realistic example to want to change from an unsorted map to a sorted map. You can't just simply switch from `{k1: v1, k2: v2}` to `sorted{k1: v1, k2: v2}` as you could do in Lisp from `(unsorted-map k1 v1 k2 v2)` to `(sorted-map k1 v1 k2 v2)`. You'd need to write out all of your operations as with the list example. And, all of a sudden you are stuck with using the unsorted data structure for your JSON serialization rather than having the ability to reach for a sorted data structure. var l = new List();
l.add(1);
l.add(2);
l.add(3);
It's also better than `var l = [1, 2, 3];`