What are the differences between decorators in TypeScript?

What are the differences between decorators in TypeScript?

In TypeScript, decorators are special annotations that can be attached to classes, methods, properties, or parameters. The main types of decorators are class decorators, method decorators, accessor decorators, property decorators, and parameter decorators. Each serves a different purpose and has its own use cases.

Can you explain class decorators and method decorators?

Sure! A class decorator is a function that takes a class constructor as an argument and can modify or replace it. For example, you can use a class decorator to add metadata to a class. On the other hand, a method decorator is a function that takes the target object, the name of the method, and the property descriptor as arguments. It can be used to modify the behavior of a method, such as logging or access control.

Are there any specific use cases for property decorators?

Yes, property decorators are often used for adding metadata to class properties, such as validation rules or default values. They can also be useful in frameworks like Angular for dependency injection.

How do I implement a simple class decorator?

To implement a simple class decorator, you define a function that takes a class as an argument and returns a new class or modifies the existing one. For example:

function MyDecorator(target: Function) {
    console.log(`Class ${target.name} is decorated!`);
}

@MyDecorator
class MyClass {}