Course Content

Object-Oriented Programming in JavaScript

1. Classes & Objects

Classes Class Attributes Class Methods Objects' Creating Keyword 'this'Constructor

2. Encapsulation

Private Modifier Get and Set

3. Static

Static Attributes Static Functions

4. Inheritance

What is an Inheritance Constructor Inheritance Overriding

Class Methods

Methods are functions that describe the class in some way. Real Students can do actions like studying, sleeping, talking, etc, so we can define it as methods of the class:


              123456789101112
            
class Student{
  name;
  university;
  age;
  gpa;
  sleep(){
    console.log('I am sleeping right now!');
  }
}

s = new Student();
s.sleep();

We added method sleep(), which prints a message.

This method is trivial, but in general, methods can also be used for:

Changing some attribute’s value
Extracting some attribute’s value
Calling other methods inside
Printing something to the console etc.

Let’s demonstrate it and add the method happyBirthday(). This method increases age of the student and prints some info about it:


              12345678910111213141516
            
class Student{
  name;
  university;
  age;
  gpa;
  sleep(){
    console.log('I am sleeping right now!');
  }
  happyBirthday(){
    this.age += 1;
    console.log('Today is my birthday!');
  }
}

s = new Student();
s.happyBirthday();

You can store some function arguments.


              12345
            
// method of the class
happyBirthday(newAge){
  this.age = newAge;
  console.log('Today is my birthday!');
}

Task

Modify sleep() method: store argument hours in it and output the message: 'I am going to sleep for '+hours+' hours' instead of the current message inside this method.

Actually you already met attributes and methods in other objects. For example, length is a attribute of some object of the class array. In the console.log(), console is a class to write some data to the stream, and log() is a method, that prints your data (like 'hello world') to the stream.

Switch to desktop for real-world practiceContinue from where you are using one of the options below

Everything was clear?

Thanks for your feedback!

Section 1. Chapter 3

Class Methods

Methods are functions that describe the class in some way. Real Students can do actions like studying, sleeping, talking, etc, so we can define it as methods of the class:


              123456789101112
            
class Student{
  name;
  university;
  age;
  gpa;
  sleep(){
    console.log('I am sleeping right now!');
  }
}

s = new Student();
s.sleep();

We added method sleep(), which prints a message.

This method is trivial, but in general, methods can also be used for:

Changing some attribute’s value
Extracting some attribute’s value
Calling other methods inside
Printing something to the console etc.

Let’s demonstrate it and add the method happyBirthday(). This method increases age of the student and prints some info about it:


              12345678910111213141516
            
class Student{
  name;
  university;
  age;
  gpa;
  sleep(){
    console.log('I am sleeping right now!');
  }
  happyBirthday(){
    this.age += 1;
    console.log('Today is my birthday!');
  }
}

s = new Student();
s.happyBirthday();

You can store some function arguments.


              12345
            
// method of the class
happyBirthday(newAge){
  this.age = newAge;
  console.log('Today is my birthday!');
}

Task

Modify sleep() method: store argument hours in it and output the message: 'I am going to sleep for '+hours+' hours' instead of the current message inside this method.

Actually you already met attributes and methods in other objects. For example, length is a attribute of some object of the class array. In the console.log(), console is a class to write some data to the stream, and log() is a method, that prints your data (like 'hello world') to the stream.

Switch to desktop for real-world practiceContinue from where you are using one of the options below

Everything was clear?

Thanks for your feedback!

Section 1. Chapter 3

Class Methods

Methods are functions that describe the class in some way. Real Students can do actions like studying, sleeping, talking, etc, so we can define it as methods of the class:


              123456789101112
            
class Student{
  name;
  university;
  age;
  gpa;
  sleep(){
    console.log('I am sleeping right now!');
  }
}

s = new Student();
s.sleep();

We added method sleep(), which prints a message.

This method is trivial, but in general, methods can also be used for:

Changing some attribute’s value
Extracting some attribute’s value
Calling other methods inside
Printing something to the console etc.

Let’s demonstrate it and add the method happyBirthday(). This method increases age of the student and prints some info about it:


              12345678910111213141516
            
class Student{
  name;
  university;
  age;
  gpa;
  sleep(){
    console.log('I am sleeping right now!');
  }
  happyBirthday(){
    this.age += 1;
    console.log('Today is my birthday!');
  }
}

s = new Student();
s.happyBirthday();

You can store some function arguments.


              12345
            
// method of the class
happyBirthday(newAge){
  this.age = newAge;
  console.log('Today is my birthday!');
}

Task

Modify sleep() method: store argument hours in it and output the message: 'I am going to sleep for '+hours+' hours' instead of the current message inside this method.

Actually you already met attributes and methods in other objects. For example, length is a attribute of some object of the class array. In the console.log(), console is a class to write some data to the stream, and log() is a method, that prints your data (like 'hello world') to the stream.

Switch to desktop for real-world practiceContinue from where you are using one of the options below

Everything was clear?

Thanks for your feedback!

Methods are functions that describe the class in some way. Real Students can do actions like studying, sleeping, talking, etc, so we can define it as methods of the class:


              123456789101112
            
class Student{
  name;
  university;
  age;
  gpa;
  sleep(){
    console.log('I am sleeping right now!');
  }
}

s = new Student();
s.sleep();

We added method sleep(), which prints a message.

This method is trivial, but in general, methods can also be used for:

Changing some attribute’s value
Extracting some attribute’s value
Calling other methods inside
Printing something to the console etc.

Let’s demonstrate it and add the method happyBirthday(). This method increases age of the student and prints some info about it:


              12345678910111213141516
            
class Student{
  name;
  university;
  age;
  gpa;
  sleep(){
    console.log('I am sleeping right now!');
  }
  happyBirthday(){
    this.age += 1;
    console.log('Today is my birthday!');
  }
}

s = new Student();
s.happyBirthday();

You can store some function arguments.


              12345
            
// method of the class
happyBirthday(newAge){
  this.age = newAge;
  console.log('Today is my birthday!');
}

Task

Modify sleep() method: store argument hours in it and output the message: 'I am going to sleep for '+hours+' hours' instead of the current message inside this method.

Actually you already met attributes and methods in other objects. For example, length is a attribute of some object of the class array. In the console.log(), console is a class to write some data to the stream, and log() is a method, that prints your data (like 'hello world') to the stream.

Switch to desktop for real-world practiceContinue from where you are using one of the options below

Section 1. Chapter 3

Switch to desktop for real-world practiceContinue from where you are using one of the options below