Overview

Implement ArrayWrapper class:

• valueOf() returns the sum of elements
• toString() returns the elements as [1,2,3] string
• Adding two wrappers sums their internal arrays

Examples

const a = new ArrayWrapper([1,2]);
const b = new ArrayWrapper([3,4]);
a + b; // 10
String(a); // '[1,2]'

Solution

class ArrayWrapper {
  constructor(nums) { this.nums = nums; }
  valueOf() { return this.nums.reduce((a, b) => a + b, 0); }
  toString() { return '[' + this.nums.join(',') + ']'; }
}