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Object-Oriented Programming in JavaScript
Object-Oriented Programming in JavaScript
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:
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.
Swipe to start coding
Create Fruit and Apple class, such that Apple is a daughter class for Fruit class. Let these classes be empty for now.
Løsning
Skift til skrivebord for at øve i den virkelige verdenFortsæt der, hvor du er, med en af nedenstående mulighederTak for dine kommentarer!
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:
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.
Swipe to start coding
Create Fruit and Apple class, such that Apple is a daughter class for Fruit class. Let these classes be empty for now.
Løsning
Skift til skrivebord for at øve i den virkelige verdenFortsæt der, hvor du er, med en af nedenstående mulighederTak for dine kommentarer!
Skift til skrivebord for at øve i den virkelige verdenFortsæt der, hvor du er, med en af nedenstående muligheder