[JS] Reverse Array
```js let arr = [1, 2, 3, 4, 5]; arr.reverse();
```js let arr = [1, 2, 3, 4, 5]; arr.reverse();
Sample shows compare two arrays and return new array with common element and not common element
This is to sort elements in an array random orders.
The key must be unique, it could be an index or unique value from the list item.
ES5 Basic Module Pattern.