solution0039N.js

// 217. Contains Duplicate
// Easy

// 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.

 

// Example 1:

// Input: nums = [1,2,3,1]
// Output: true
// Example 2:

// Input: nums = [1,2,3,4]
// Output: false
// Example 3:

// Input: nums = [1,1,1,3,3,4,3,2,4,2]
// Output: true
 

// Constraints:

// 1 <= nums.length <= 105
// -109 <= nums[i] <= 109

/**
 * @param {number[]} nums
 * @return {boolean}
 */
var containsDuplicate = function(nums) {
    const  unique = new Set(nums)
    return unique.size !== nums.length
      }

    console.log(containsDuplicate([1,2,3,4]));