Object-Oriented Programming

Objects

Objects allows us to store functions with their associated data.

Object Literal way

const user1 = {

name: "Dan",

score: "100",

increment: function() {

user1.score++;

}

//Can easily add more functionality

decrement: function() {

user1.score--;

}

}

Dot Notation

const user2 = {};

user2.name = "Dog"

user2.score = 5;

user2.increment = function () {user2.score++;};

Object.create -- Bad Approach

const user3 = Object.create(null)

user3.name = "Dog2"

user3.score = 9;

user3.increment = function() {user3.score++;};

Generating Objects using functions

• Defining functions inside of a object creator would lead to extreme unoptimizations as each instantiation would contain the functions.
• Prototype chain is a better way of doing this. If you want to add an increment function to every instance of user.

Object.create -- Better Approach

function userCreator (name, score {

const newUser = Object.create(userFunctionScore);

newUser.name = name;

newUser.score = score;

return newUser;

}

const userFunctionStore = {

increment: function() {this.score++;},

login: function() {console.log("You're loggedin");}

}

const user1 = userCreator("Phil", 4);

const user2 = userCreator("Dog", 5);

user1.increment();

• As soon as you declare new user with Object.create, it returns an empty object but with hidden properties which referrence to any function that's been passed in the Object.create paramaters.
• If JS does not find the property in an object it goes and look up in the __proto__ hidden property.

The new & this keywords -- Functions & Objects

• new keyword automates creating the user object and returning the user object. So we don't need to do Object.create or return
• Function defined with the function keyword are a function-object combo and can act as an object. If you use dot notation ,you can access its object bits. It does not overwrite or lose access to the function bits.
• functions contain the prototype property which itself is an object to replace our __proto__ in objects
• The new keyword does the following:
  • Bind this: { } to any objecy
  • Calls the __proto__ binding on the objec
  • returns the object