Bun middleware that allows you to extend Response

[EvHaus]

👋 Hey. It's me again.

I'm trying to implement a CORS middleware in Bun that adds some additional headers to all responses. This is proving to be quite difficult at the moment. I see you have this example but that's not quite enough to fully handle CORS headers. I'm trying to do something more like this.

I'm wondering if it would be possible for middleware in Bun to be able to extend the Response object somehow. At the moment, await next() in middleware returns undefined. It would be great if it returned the response of the promise chain.

Ideally, I would like to write a middleware like this:

import type { NextFunction } from 'node-file-router';

const headers = async (req: Request, next: NextFunction) => {
	const res = await next();

	// Ensure all API requests always return these headers
	res.headers.set('Access-Control-Allow-Origin', '*');
	res.headers.set('Access-Control-Allow-Methods', 'GET, POST, PUT, DELETE, OPTIONS');

	return res;
};

export default headers;

Do you think this would be possible to add support for?

[Danilqa]

@EvHaus Hey! 👋 Nice to meet you!

Cool, sure, I had the same thought earlier as well! It will be delivered tomorrow.
One thing to keep in mind: if your CORS middleware is positioned as follows:
[useLogger] -> [useCors] -> [useAuth].

then useAuth should also return next:

export async function useAuth(req: Request, next: NextFunction) {
  // ...

  return next();
}

[Danilqa]

@EvHaus Hey! I've released version 0.6.0 with this feature :) Please feel free to reach out if you have any issues or additional suggestions. The documentation can be found here, and it aligns with what you described earlier.

[EvHaus]

Works beautifully! Thanks again @Danilqa. I really appreciate your fast reponses and updates to the library.