let mySet = new Set();

let animal = {name: 'Cat'};
let car = {name: 'Honda CRV'};
let game = {name: 'Overwatch'};
let band = {name: '0.1g no Gosan'};

mySet.add(animal);
mySet.add(car);
mySet.add(car);
mySet.add(car);
mySet.add(game);
mySet.add(band);
mySet.add({name: 'Overwatch'});
mySet.add({name: 'Overwatch'});

console.log(mySet.size);
//6