3sum.js

/**
 * @param {number[]} nums
 * @return {number[][]}
 */
var threeSum = function(nums) {
    let ret = {}; //new Set();
    const arr = nums;
    
    
    for (let i = 0; i < arr.length - 2; i++) {
        for (let j = i + 1; j < arr.length - 1; j++) {
            for (let k = j + 1; k < arr.length; k++) {
                if (arr[i] + arr[j] + arr[k] == 0) {
                    ret[[arr[i], arr[j], arr[k]].sort()] = true;
                }
            }
        }
    }
    
    return Object.keys(ret).map(s => s.split(","));
};