shift and unshift js

let cats = ['Bob', 'Willy', 'Mini'];

cats.shift(); // ['Willy', 'Mini']

let cats = ['Bob']; 

cats.unshift('Willy'); // ['Willy', 'Bob']

cats.unshift('Puff', 'George'); // ['Puff', 'George', 'Willy', 'Bob']