fix: handle calling writable.end() correctly

[ezg27]

Hi there! It looks like a bug was introduced in v1.2.2 with the addition of writeFromReadableStream in this PR. I was able to reproduce this on both Node v18 and v20.

With fast responses on a fast connection the problem isn't as noticeable, but if you're serving large responses (particularly if the response returned from a Hono handler is a ReadableStream that's slow to enqueue chunks), then writable.end() in writeFromReadableStream is never called. This leads to responses in the browser showing as 'Pending' indefinitely.

I've created a reproduction repo here that demonstrates the issue - try adding a log inside the if (done) {...} statement in the flow function in node_modules/@hono/node-server/dist/index.mjs and you'll see it never gets logged. The reproduction returns an image response as a stream, with a short artificial delay inserted before each chunk is enqueued to better reproduce the problem.

The changes in this PR align more closely with this example from the Node.js documentation, where a single-use drain listener is registered with writable.once each time writable.write returns false. This should ensure that write calls are properly paused + resumed and the stream read to the end with the writable closed successfully.

Let me know if you would prefer a different approach or if there's anything else you'd like me to add to this 🙂

[yusukebe]

Hi @ezg27 !

Thanks for the PR and creating the project to reproduce the bug. Looks good. I'll merge it now!

[sjc5]

This fixed an issue for me as well. Thank you!