text: class User {
      constructor(firstName, lastName, email) {
          this.firstName = firstName;
          this.lastName = lastName;
          this.email = email;
      }
  
      greet() {
          console.log(`Hi! I am ${this.firstName} ${this.lastName}`);
      }
  }
  
  let user = new User("John", "Doe", "johndoe@gmail.com");
  user.greet = user.greet.bind(user);
  user.greet.call({firstName: "Jane", lastName: "Doe"});
  var foobar = {
      firstName: "Foo",
      lastName: "Bar"
  };
  user.greet.apply(foobar);