The first and very important question, is JavaScript really an object-oriented programming (OOP) language? In my personal opinion, I will say: NO at all; JavaScript, emulates object classes via constructor functions.

But first, what is Object-Oriented Programming?

A programming paradigm centered around objects rathen than functions.

Mosh is one of the best tutors I have ever met, and I don’t want to copy a ton of text, and I personally don’t want to explain and transcribe a lot of content that can be better understood through a video.

Also, this is a very interesting resource in Medium: A Guide to Object-Oriented Programming in JavaScript and of course this from Eric Ellioot Master the JavaScript Interview: What’s the Difference Between Class & Prototypal Inheritance?.

I made an easy example:

class Person  {
  constructor(firstName, age) {
    this.firstName = firstName;
    this.age = age;
  }

  static getAge(person) {
    return person.age;
  }

  greeting() {
    return `Hello ${this.firstName}`;
  }
}

class Teacher extends Person {
  constructor(firstName, age, id, seniority) {
    super(firstName, age);
    this.id = id;
    this.seniority = seniority;
  }

  set teacherId(newId) {
    this.id = newId;
  }

  get teacherId() {
    return this.id;
  }
}

And now, the most important part, how can I check if this works?

const newPerson = new Person('Andres', 35);
Person.getAge(newPerson); // 35
newPerson.greeting(); // "Hello Andres"

const newTeacher = new Teacher('SrHart', 53, 13579, 'Senior');
newTeacher.teacherId = 24680;
newTeacher.teacherId; // 24680
newTeacher.greeting(); // "Hello SrHart"