Edit in JSFiddle

let obj = {
  name: 'sachin',
  age: 30,
  favFood: ['pizza', 'ice-cream']
};

let clone = JSON.parse(JSON.stringify(obj));
clone.favFood.pop();
clone.favFood.push('sandwich');

console.log(JSON.stringify(obj, null, 2));
console.log(JSON.stringify(clone, null, 2));