const getList = ([x, ...y]) => [x, y];
const getUser = user => {name: user.name, age: user.age};
const list = [1, 2, 3, 4];
const user = { name: 'Lydia', age: 21 };
console.log(getList(list)); // [1, [2, 3, 4]]
console.log(getUser(user)); // undefined
