How do I create a parameter decorator in TypeScript?

How do I create a parameter decorator in TypeScript?

To create a parameter decorator in TypeScript, you can define a function that takes three parameters: target, propertyKey, and parameterIndex.

Can you show me a simple example of a parameter decorator?

Sure! Here's a basic example:

function LogParameter(target: any, propertyKey: string, parameterIndex: number) {
    console.log(`Parameter at index ${parameterIndex} in ${propertyKey} was decorated.`);
}

class Example {
    greet(@LogParameter name: string) {
        return `Hello, ${name}!`;
    }
}

This decorator logs the parameter index whenever the greet method is called.

What are some use cases for parameter decorators?

Parameter decorators can be used for logging, validation, or modifying the behavior of parameters in methods, enhancing code readability and maintainability.