/**
 * @param {number[]} nums
 * @param {number} target
 * @return {number[]}
 */
var twoSum = function(nums, target) {
    let map = {};
  for (let i = 0; i < nums.length; i++) {

    let compliment = target - nums[i];
    if (map[compliment]) {
      return [(map[compliment] - 1), i];
    } else {
      map[nums[i]] = i + 1;
    }

  }
};