40_index40.js

// new keyword example
//1) it creates empty object like this = {}
//2) return this;
//3)  const this = Object.create(CreateUser.prototype)



// __proto__
// official ecmascript document
// [[prototype]]

//constructor function 
function CreateUser(firstName , lastName , email, age , address){
    // this new ={} we don't need to create empty object beause this task is already done by new keyword.
    this.firstName = firstName;
    this.lastName = lastName;
    this.email = email;
    this.age = age;
    this.address = address; 
    // return this; we don't need to return "this" because this task is already done by new keyword.
}

CreateUser.prototype.about = function(){
    return `${this.firstName}  is ${this.age} years old.`;
};
CreateUser.prototype.is18 = function(){
    return this.age >= 18;
}
CreateUser.prototype.sing = function(){
    return "la la la la";
}

const user1 = new CreateUser('manish','Tomar','manishtomar00mt@gmail.com',23, "delhi");
const user2 = new CreateUser('Sonal','Mishra','manishtomar00mt@gmail.com',23, "delhi");
const user3 = new CreateUser('Varun','Tomar','varuntomar3233@gmail.com',18, "delhi");

console.log(user1);
user1.is18();


//convention of javascript
//name of construction function should be start captial letter like CreateUser in above example.