Evaluate all possible combinations of array items

all-combinations.js

var arr = ["a","b","c","d","e","f","g","h","i","j"];

for(i = 0; i <= Math.pow(2,arr.length)-1; i++){

	var mask = i;
	console.log("-------------------------------------" + mask);
	var combination = "";
	for(y=0; y<arr.length; y++){
		if((mask & Math.pow(2,y)) == Math.pow(2,y)) combination += " " + arr[y];
	}
	console.log(combination);
	
}