Objects inside classes in OOP in JavaScript

Classes can use objects of other classes. Let's look at an example. Let's say we want to make a user with a first and last name, as well as the city in which he lives. Let's say we have the following class for the city:

javascriptclass City {
  constructor(name) {
    this.name = name;
  }
}

We will pass the name, surname and city as parameters of the constructor:

javascriptclass User {
  constructor(name, surn, city) {
    this.name = name;
    this.surn = surn;
    this.city = city;
  }
}

In this case, the first and last name will be strings, but the city will be an object of its own separate class:

javascriptlet city = new City('luis');
let user = new User('john', 'smit', city);

Let's output the name of our user:

javascriptconsole.log(user.name);

Now let's display the name of the city for our user:

javascriptconsole.log(user.city.name);

javascriptclass Employee {
  constructor(name, position, department) {
    this.name = name;
    this.position = position;
    this.department = department;
  }
}