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Object-Oriented Programming in JavaScript
course content

Course Content

Object-Oriented Programming in JavaScript

Object-Oriented Programming in JavaScript

1. Classes & Objects
ClassesClass AttributesClass MethodsObjects' Creating Keyword 'this'Constructor
2. Encapsulation
Private ModifierGet and Set
3. Static
Static AttributesStatic Functions
4. Inheritance
What is an InheritanceConstructor InheritanceOverriding

bookConstructor

Constructor is used for object creation and specifying some attributes. Look at this statement:


              
1

            
student = new Student();
copy

Student() is a constructor of class Student, so the student variable is now a Student object.

This simple constructor is using by default and creates an object only. But you can define a constructor that will initialize some object attributes.


              
1

            
student = new Student('Robert', 22);
copy

student object now has name Robert and age 22.

The syntax of the constructor inside the class is following:


              
12345678910111213141516171819202122

            
class Student{
  name;
  university;
  age;
  gpa;

  constructor(name, age){
    this.name = name;
    this.age = age;
  console.log('Student created');
  }

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

student = new Student('Robert', 22);
copy

By object creating, you can pass some arguments and use them inside constructor. But note that skipped parameters will have undefined value. Look at the example and run it to see what happens.


              
123456789101112131415

            
class Student{
  name;
  age;
  gpa;
  constructor(name, age, gpa){ // constructor with 3 parameters
    this.name = name;
    this.age = age;
    this.gpa = gpa;
    console.log('Student created');
  }
}

student = new Student('Robert', 22); // pass only 2 values
console.log(JSON.stringify(student));
// object has only 2 defined properties name and age
copy

Only name and age properties are defined in student object because of 2 arguments while student initialization.

Pass the arguments in order they are defined in constructor.

Task

Extend existing constructor with arguments for university and gpa attributes. After that, change the line of object initialization by adding 2 more arguements inside Student() statement.

Switch to desktopSwitch to desktop for real-world practiceContinue from where you are using one of the options below
Everything was clear?

How can we improve it?

Thanks for your feedback!

Section 1. Chapter 6
toggle bottom row

bookConstructor

Constructor is used for object creation and specifying some attributes. Look at this statement:


              
1

            
student = new Student();
copy

Student() is a constructor of class Student, so the student variable is now a Student object.

This simple constructor is using by default and creates an object only. But you can define a constructor that will initialize some object attributes.


              
1

            
student = new Student('Robert', 22);
copy

student object now has name Robert and age 22.

The syntax of the constructor inside the class is following:


              
12345678910111213141516171819202122

            
class Student{
  name;
  university;
  age;
  gpa;

  constructor(name, age){
    this.name = name;
    this.age = age;
  console.log('Student created');
  }

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

student = new Student('Robert', 22);
copy

By object creating, you can pass some arguments and use them inside constructor. But note that skipped parameters will have undefined value. Look at the example and run it to see what happens.


              
123456789101112131415

            
class Student{
  name;
  age;
  gpa;
  constructor(name, age, gpa){ // constructor with 3 parameters
    this.name = name;
    this.age = age;
    this.gpa = gpa;
    console.log('Student created');
  }
}

student = new Student('Robert', 22); // pass only 2 values
console.log(JSON.stringify(student));
// object has only 2 defined properties name and age
copy

Only name and age properties are defined in student object because of 2 arguments while student initialization.

Pass the arguments in order they are defined in constructor.

Task

Extend existing constructor with arguments for university and gpa attributes. After that, change the line of object initialization by adding 2 more arguements inside Student() statement.

Switch to desktopSwitch to desktop for real-world practiceContinue from where you are using one of the options below
Everything was clear?

How can we improve it?

Thanks for your feedback!

Section 1. Chapter 6
toggle bottom row

bookConstructor

Constructor is used for object creation and specifying some attributes. Look at this statement:


              
1

            
student = new Student();
copy

Student() is a constructor of class Student, so the student variable is now a Student object.

This simple constructor is using by default and creates an object only. But you can define a constructor that will initialize some object attributes.


              
1

            
student = new Student('Robert', 22);
copy

student object now has name Robert and age 22.

The syntax of the constructor inside the class is following:


              
12345678910111213141516171819202122

            
class Student{
  name;
  university;
  age;
  gpa;

  constructor(name, age){
    this.name = name;
    this.age = age;
  console.log('Student created');
  }

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

student = new Student('Robert', 22);
copy

By object creating, you can pass some arguments and use them inside constructor. But note that skipped parameters will have undefined value. Look at the example and run it to see what happens.


              
123456789101112131415

            
class Student{
  name;
  age;
  gpa;
  constructor(name, age, gpa){ // constructor with 3 parameters
    this.name = name;
    this.age = age;
    this.gpa = gpa;
    console.log('Student created');
  }
}

student = new Student('Robert', 22); // pass only 2 values
console.log(JSON.stringify(student));
// object has only 2 defined properties name and age
copy

Only name and age properties are defined in student object because of 2 arguments while student initialization.

Pass the arguments in order they are defined in constructor.

Task

Extend existing constructor with arguments for university and gpa attributes. After that, change the line of object initialization by adding 2 more arguements inside Student() statement.

Switch to desktopSwitch to desktop for real-world practiceContinue from where you are using one of the options below
Everything was clear?

How can we improve it?

Thanks for your feedback!

Constructor is used for object creation and specifying some attributes. Look at this statement:


              
1

            
student = new Student();
copy

Student() is a constructor of class Student, so the student variable is now a Student object.

This simple constructor is using by default and creates an object only. But you can define a constructor that will initialize some object attributes.


              
1

            
student = new Student('Robert', 22);
copy

student object now has name Robert and age 22.

The syntax of the constructor inside the class is following:


              
12345678910111213141516171819202122

            
class Student{
  name;
  university;
  age;
  gpa;

  constructor(name, age){
    this.name = name;
    this.age = age;
  console.log('Student created');
  }

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

student = new Student('Robert', 22);
copy

By object creating, you can pass some arguments and use them inside constructor. But note that skipped parameters will have undefined value. Look at the example and run it to see what happens.


              
123456789101112131415

            
class Student{
  name;
  age;
  gpa;
  constructor(name, age, gpa){ // constructor with 3 parameters
    this.name = name;
    this.age = age;
    this.gpa = gpa;
    console.log('Student created');
  }
}

student = new Student('Robert', 22); // pass only 2 values
console.log(JSON.stringify(student));
// object has only 2 defined properties name and age
copy

Only name and age properties are defined in student object because of 2 arguments while student initialization.

Pass the arguments in order they are defined in constructor.

Task

Extend existing constructor with arguments for university and gpa attributes. After that, change the line of object initialization by adding 2 more arguements inside Student() statement.

Switch to desktopSwitch to desktop for real-world practiceContinue from where you are using one of the options below
Section 1. Chapter 6
Switch to desktopSwitch to desktop for real-world practiceContinue from where you are using one of the options below
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