What are decorator factories in TypeScript?

What are decorator factories in TypeScript?

Decorator factories are functions that return decorators. They allow you to create dynamic decorators with parameters.

Can you give me an example of a decorator factory?

Sure! Here's a simple example:

function Log(message: string) {
    return function(target: any, propertyKey: string, descriptor: PropertyDescriptor) {
        console.log(`${message}: ${propertyKey}`);
    };
}

This factory creates a decorator that logs a message when the decorated method is called.

How do I use this decorator factory in a class?

You can use it like this:

class Example {
    @Log('Calling method')
    myMethod() {
        console.log('Method executed');
    }
}

When myMethod is called, it will log 'Calling method: myMethod'.

What are some common use cases for decorator factories?

Common use cases include logging, access control, and validation. They help in adding reusable behavior to classes and methods.