Check if res is sent / ended with Express

Question

Using Express, how can I determine the response has been sent / that the response has been completely written to?

app.use((req,res,next) => {

   if(res.ended){
     //
   }

   if(res.finished){
     //
   }

});

how can I tell if res.end() has been called? I am looking for a boolean I can read on res.

Cleodell

Keep in mind that the usual way of programming Express is that you don't call next() after you call res.send() so a middleware like you show above that you put at the end of the middleware chain would never get called. – Autosome

thanks for that tip @Autosome that sounds about right – Cleodell

Answer 1

response.end() will set response.finished if it's been called, as per the documentation.

Slacken

What if the response is closed from the other side? – Alexandraalexandre

I'm not sure what the current behaviour in Express is, so you may need to experiment. A different event is emitted and no further callbacks are made, far as I know, but each callback gets to run to completion. – Slacken

res.finished is deprecated, you can use response.writableEnded or request.writableFinished depending what you want. – Slimsy

@Slimsy If this answer is out of date and you know how it works in the current Express it may be worth posting an alternate answer. – Slacken

Answer 2

Use res.writableEnded (docs).

res.finished is deprecated (see).

Blackfish

Well, res.writableEnded is not working for my in latest (2022) Express and latest node (16). – Indult