Showing an example of mutation of an array within an object cloned with spread operator

nested-object-mutation.js

const pokemon = {
  name: 'Squirtle',
  type: 'Water',
  abilities: ['Torrent', 'Rain Dish']
};

const squirtleClone = { ...pokemon };
pokemon.name = 'Charmander';
pokemon.abilities.push('Surf');

console.log(squirtleClone); //Result: { name: 'Squirtle', type: 'Water', abilities: [ 'Torrent', 'Rain Dish', 'Surf' ] }