var contact = {name: 'Alice', email: 'alice@example.com'};
var partialContact = {name: 'Bob'};
_.defaults(partialContact, {name: '', email: '', phone: ''}); // partialContact is now {name: 'Bob', email: '', phone: ''}This ensures that every contact object has the same set of properties, even if some data is incomplete. _.defaults is a function provided by the Underscore library.