Leet code question

1.  Example 1:
   
    Input: nums = [1,2,3,1]
    Output: true
    Example 2:
   
    Input: nums = [1,2,3,4]
    Output: false
    Example 3:
    // code 
    function containsDuplicate(nums){
      // creating set using nums
       const isDuplicate=new Set(nums);
      // checking if created set and nums length are eqaul
       if(isDuplicate.size===nums.length){
        return false;
       }
       return true;
    }