2 ways of solving "Two Sum" coding interview problem in JavaScript.

twoSum.js

// var twoSum = function(nums, target) {
//     for(index = 0; index < nums.length - 1; index++) {
//         for(i = index+1; i< nums.length; i++) {
//             let sum = nums[index] + nums[i];
//             if (sum == target) {
//                 return [index, i];
//             }
//         }
//     }
// };

var twoSum = function(nums, target) {
    let d = {};
    for(i = 0; i< nums.length; i++) {
        if (d[target-nums[i]] >= 0) {
            return [d[target-nums[i]], i];
        }
        d[nums[i]] = i;
    }
};

const nums = [2, 7, 11, 15];
const target = 9;
console.log(twoSum(nums, target));