2695. Array Wrapper.js

/*

Create a class ArrayWrapper that accepts an array of integers in it's 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].
 

Example 1:

Input: nums = [[1,2],[3,4]], operation = "Add"
Output: 10
Explanation:
const obj1 = new ArrayWrapper([1,2]);
const obj2 = new ArrayWrapper([3,4]);
obj1 + obj2; // 10
Example 2:

Input: nums = [[23,98,42,70]], operation = "String"
Output: "[23,98,42,70]"
Explanation:
const obj = new ArrayWrapper([23,98,42,70]);
String(obj); // "[23,98,42,70]"
Example 3:

Input: nums = [[],[]], operation = "Add"
Output: 0
Explanation:
const obj1 = new ArrayWrapper([]);
const obj2 = new ArrayWrapper([]);
obj1 + obj2; // 0
 

Constraints:

0 <= nums.length <= 1000
0 <= nums[i] <= 1000
Note: nums is the array passed to the constructor

*/

/**
 * @param {number[]} nums
 */
var ArrayWrapper = function(nums) {
    this.nums = (nums ?? []).slice();
};

ArrayWrapper.prototype.valueOf = function() {
    return this.nums.reduce((r, v) => r + v, 0);
}

ArrayWrapper.prototype.toString = function() {
    return '[' + this.nums.join() + ']';
}

/**
 * const obj1 = new ArrayWrapper([1,2]);
 * const obj2 = new ArrayWrapper([3,4]);
 * obj1 + obj2; // 10
 * String(obj1); // "[1,2]"
 * String(obj2); // "[3,4]"
 */