angular.service vs angular.factory

Question

I have seen both angular.factory() and angular.service() used to declare services; however, I cannot find angular.service anywhere in official documentation.

Answer 1

Simply put ..

const user = {
  firstName: 'john'
};

// Factory
const addLastNameFactory = (user, lastName) => ({
  ...user,
  lastName,
});

console.log(addLastNameFactory(user, 'doe'));

// Service
const addLastNameService = (user, lastName) => {
  user.lastName = lastName; // BAD! Mutation
  return user;
};

console.log(addLastNameService(user, 'doe'));