Day 29: Array Wrapper

Create a class ArrayWrapper that accepts an array of integers in its constructor. This class should have two features:

When two instances of this class are added together with the + operator, the resulting value is the sum of all the elements in both arrays.
When the String() function is called on the instance, it will return a comma separated string surrounded by brackets. For example, [1,2,3].

var ArrayWrapper = function(nums) {
    
};

Example 1:
Input: nums = [[1,2],[3,4]], operation = "Add"
Output: 10

Example 2:
Input: nums = [[23,98,42,70]], operation = "String"
Output: "[23,98,42,70]"

Example 3:
Input: nums = [[],[]], operation = "Add"
Output: 0