Difference between 'extends' and 'implements' in TypeScript

#typescript #oop

Today, a friend ask about the difference between extends and implements.

class Media {
  format: string;
}
class Video extends Media {}
class Image implements Media {}

The short answer for him was:

extends: The class get all these methods and properties from the parent, so you don't have to implement.

implements: The class has to implement methods and properties.

I hope this is can help someone with the same question.

Latest comments (2)

Behzad Khodapanah • May 17 '22 • Edited

Thanks for helpful post!
I want add more info.
When we are using EXTENDS: the class that extended by become the parent, and there our class has access to all the properties and methods.
When we are using IMPLEMENTS: the class has to implement the destination class methods and properties without being the child of that class!

Final thought: Extends is more like inheritance and Implements more like polymorphism.