Contains Duplicate

Given an integer array nums, return true if any value appears at least twice in the array, and return false if every element is distinct. :contentReference[oaicite:1]1

Input: nums = [1, 2, 3, 1]

Output: true

/**
 * @param {number[]} nums
 * @return {boolean}
 */
var containsDuplicate = function (nums) {
  let unique = {};

  for (let n of nums) {
    if (unique[n] == undefined) {
      unique[n] = 1;
    } else {
      return true;
    }
  }

  return false;
};

const nums = [1, 2, 3, 1];
const result = containsDuplicate(nums);
console.log(result);