What are the differences between decorators in JavaScript and TypeScript?

What are the differences between decorators in JavaScript and TypeScript?

In JavaScript, decorators are not natively supported, but you can use experimental features or libraries. TypeScript, however, has built-in support for decorators, allowing you to use them more easily with classes and methods.

Can you give me an example of a decorator in TypeScript?

Sure! Here's a simple example of a class decorator in TypeScript:

function LogClass(target: Function) {
    console.log(`Class ${target.name} is created.`);
}

@LogClass
class MyClass {
    constructor() {
        console.log('MyClass instance created.');
    }
}

This decorator logs a message when the class is created.

How do decorators affect performance in TypeScript?

Decorators can introduce some overhead, as they add additional logic during class creation. However, the impact is usually minimal unless used extensively. It's important to profile your application if performance is a concern.

Are there any limitations to using decorators in TypeScript?

Yes, decorators in TypeScript have some limitations, such as not being able to decorate certain types of declarations like interfaces or enums. Additionally, they require the experimentalDecorators compiler option to be enabled.