The solution of the task https://leetcode.com/problems/permutations/ by using Heap's Algorithm

heapsAlgorithm.js

/**
 * Link on the task: https://leetcode.com/problems/permutations/
 * Description: Given an array nums of distinct integers, return all the possible permutations. You can return the answer in any order.
 * Example:
 * Input: nums = [1,2,3]
 * Output: [[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]]
 */

const permute = function(nums) {
    return (function permutationHeap(array, n, res = []) {
        n = n || array.length;
        if (n === 1) {
            res.push([...array])
        } else {
            for (let i = 1; i <= n; i++) {
                permutationHeap(array, n - 1, res);
                if (n % 2) {
                    [array[0], array[n - 1]] = [array[n - 1], array[0]];
                } else {
                    [array[i - 1], array[n - 1]] = [array[n - 1], array[i - 1]];
                }
            }
        }
        return res;
    })(nums);
};


console.log(permute(["a", "b", "c"]));