Longest Consecutive Sequence

Input: nums = [100,4,200,1,3,2]Output: 4Explanation: The longest consecutive elements sequence is [1, 2, 3, 4]. Therefore its length is 4.

var longestConsecutive = function (nums) {    let num_set = new Set(nums);    let longestStreak = 0;    for (let num of nums) {        if (!num_set.has(num - 1)) {            let currentNum = num;            let currentStreak = 1;            while (num_set.has(currentNum + 1)) {                currentNum += 1;                currentStreak += 1;            }            longestStreak = Math.max(longestStreak, currentStreak);        }    }    return longestStreak;}