1function powerSet(arr) {
2  
3  // the final power set
4  var powers = [];
5  
6  // the total number of sets that the power set will contain
7  var total = Math.pow(2, arr.length);
8  
9  // loop through each value from 0 to 2^n
10  for (var i = 0; i < total; i++) {
11    
12    // our set that we add to the power set
13    var tempSet = [];
14    
15    // convert the integer to binary
16    var num = i.toString(2);
17    
18    // pad the binary number so 1 becomes 001 for example
19    while (num.length < arr.length) { num = '0' + num; }
20    
21    // build the set that matches the 1's in the binary number
22    for (var b = 0; b < num.length; b++) {
23      if (num[b] === '1') { tempSet.push(arr[b]); }    
24    }
25    
26    // add this set to the final power set
27    powers.push(tempSet);
28    
29  }
30  
31  return powers;
32  
33}
34
35powerSet([1, 2, 3]); 
36