What is the difference between implements and extends?

Class inheritance vs interface implementation.

What You'll Learn

extends for inheritance
implements for interfaces
When to use each

extends (Inheritance)

code.tsTypeScript

class Animal {
  name: string;

  constructor(name: string) {
    this.name = name;
  }

  move(): void {
    console.log(`${this.name} is moving`);
  }
}

class Dog extends Animal {
  breed: string;

  constructor(name: string, breed: string) {
    super(name); // Call parent constructor
    this.breed = breed;
  }

  bark(): void {
    console.log("Woof!");
  }
}

implements (Interface)

code.tsTypeScript

interface Printable {
  print(): void;
}

interface Loggable {
  log(message: string): void;
}

// Can implement multiple interfaces
class Document implements Printable, Loggable {
  print(): void {
    console.log("Printing...");
  }

  log(message: string): void {
    console.log(message);
  }
}

Key Differences

extends	implements
Inherits implementation	Must provide implementation
Single inheritance only	Multiple interfaces allowed
For classes	For interfaces

How do Classes work in TypeScript?

What are Decorators in TypeScript?