how to update objects in locall storage
// Get the existing data
var existing = localStorage.getItem('myFavoriteSandwich');
// If no existing data, create an array
// Otherwise, convert the localStorage string to an array
existing = existing ? existing.split(',') : [];
// Add new data to localStorage Array
existing.push('tuna');
// Save back to localStorage
localStorage.setItem('myFavoriteSandwich', existing.toString());