README.md

What is a class?

A blueprint for creating objects with pre-defined properties and methods.

Does JavaScript really have them?
==> Ehh....not really

Why do we need to learn this?

We're going to implement data structures as classes!

THE SYNTAX

class Student {
    constructor(firstName, lastName){
        this.firstName = firstName;
        this.lastName = lastName;
    }
}

The method to create new objects must be called constructor

The class keyword creates a constant, so you can not redefine it. Watch out for the syntax as well!

Creating objects from classes

We use the new keyword

class Student {
    constructor(firstName, lastName){
        this.firstName = firstName;
        this.lastName = lastName;
    }
}

let firstStudent = new Student("Colt", "Steele");
let secondStudent = new Student("Blue", "Steele");

Instance Methods

class Student {
    constructor(firstName, lastName){
        this.firstName = firstName;
        this.lastName = lastName;
    }
    fullName(){
        return `Your full name is ${this.firstName} ${this.lastName}`;
    }
}

let firstStudent = new Student("Colt", "Steele");

firstStudent.fullName() // "Colt Steele"

Class Methods

class Student {
    constructor(firstName, lastName){
        this.firstName = firstName;
        this.lastName = lastName;
    }
    
    fullName(){
        return `Your full name is ${this.firstName} ${this.lastName}`;
    }
     
    //class Methods
    static enrollStudents(...students){
        // maybe send an email here
    }
}

let firstStudent = new Student("Colt", "Steele");
let secondStudent = new Student("Blue", "Steele");

Student.enrollStudents([firstStudent, secondStudent])

How we'll be using classes

class DataStructure(){
    constructor(){
        // what default properties should it have?
    }
    someInstanceMethod(){
        // what should each object created from this class be able to do?
    }
}

We will be using the constructor and instance methods quite a bit!

We will almost never be using static methods

One gotcha with this

Inside all of our instance methods and constructor, the keyword this refers to the object created from that class (also known as an instance)

Recap

• Classes are blueprints that when created make objects known as instances
• Classes are created with the new keyword
• The constructor function is a special function that gets run when the class is instantiated
• Instance methods can be added to classes similar to methods in objects
• Class methods can be added using the static keyword