What is an Inheritance

Inheritance is another main OOP principle, which means that some classes can adopt properties of other classes, and maybe extend them.

Like, for example, we have class Rectangle which represents the rectangle instance. Then, let’s define class Square. Square is a Rectangle, too, so we can create this class from the Rectangle class. Use keyword extends:


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class Rectangle {
  height;
  width;
  constructor(height, width) {
    this.height = height;
    this.width = width;
    console.log('Rectangle created');
  }
}

class Square extends Rectangle{
}

Now Square has the same attributes and methods as Rectangle class.

The Rectangle is a base class, and Square is a derived class. Or you can say that Rectangle is a parent class and Square is a daughter class.

Square differs with sides length: height is equal to the width, unlike for Rectangle.

Usually, JavaScript classes such as an array, console, window, etc. inherit some base classes, which can inherit other classes. It is very advisable to extend existing classes, not to define similar classes again.

Task

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Create Fruit and Apple class, such that Apple is a daughter class for Fruit class. Let these classes be empty for now.

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Everything was clear?

Thanks for your feedback!

Section 4. Chapter 1

What is an Inheritance

Inheritance is another main OOP principle, which means that some classes can adopt properties of other classes, and maybe extend them.


              123456789101112
            
class Rectangle {
  height;
  width;
  constructor(height, width) {
    this.height = height;
    this.width = width;
    console.log('Rectangle created');
  }
}

class Square extends Rectangle{
}

Now Square has the same attributes and methods as Rectangle class.

The Rectangle is a base class, and Square is a derived class. Or you can say that Rectangle is a parent class and Square is a daughter class.

Square differs with sides length: height is equal to the width, unlike for Rectangle.

Task

Swipe to show code editor

Create Fruit and Apple class, such that Apple is a daughter class for Fruit class. Let these classes be empty for now.

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 4. Chapter 1

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