Constructor Functions

What is a Constructor Function?

• function that creates an object class
• allows you to create multiple instances of the class

Example of Constructor Function

function User(firstName, lastName, age, gender) {
  this.firstName = firstName;
  this.lastName = lastName;
  this.age = age;
  this.gender = gender;
}

var user1 = new User('John', 'Doe', 35, 'male');
console.log(user1); // $: User {firstName: "John", lastName: "Doe", age: 35, gender: "male"}

// Use prototype to add property to all instances of User
User.prototype.emailDomain = '@gmail.com';

console.log(user1.emailDomain); // @gmail.com

// Use prototype to add functionality to all instances of User
User.prototype.getEmail = function () {
  return this.firstName + this.lastName + this.emailDomain;
};

user1.getEmail(); // $: "JohnDoe@gmail.com"