02-UsingSets.js

var set = new Set();

set.add(1);
console.log(set.values()); //outputs ["1"]
console.log(set.has(1));   //outputs true
console.log(set.size());   //outputs 1

set.add(2);
console.log(set.values()); //outputs ["1", "2"]
console.log(set.has(2));   //true
console.log(set.size());   //2
console.log(set.sizeLegacy());   //3

set.remove(1);
console.log(set.values()); //outputs ["2"]

set.remove(2);
console.log(set.values()); //outputs []