Returns all possible subsets (without duplicate subsets)

unique.js

let list = [];
let nums = [1,2,3]; 

function backtrack(nums, temparray, startindex) {
    list.push(temparray.slice());
    
    for (var i = startindex; i < nums.length; i++) {
        temparray.push(nums[i]);
        backtrack(nums, temparray, i + 1);
        temparray.pop(); 
    }
};

backtrack(nums, [], 0);

console.log(list);