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.

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. — jfriend00, Aug 23 '19 at 00:25

score 11 · Answer 1 · answered Jun 04 '20 at 00:41

11

Use res.writableEnded (docs).

res.finished is deprecated (see).

answered Jun 04 '20 at 00:41

vitaliydev

Well, `res.writableEnded` is not working for my in latest (2022) Express and latest node (16). – Vasyl Boroviak Sep 26 '22 at 06:35

score 4 · Accepted Answer · answered Aug 23 '19 at 00:09

4

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

answered Aug 23 '19 at 00:09

tadman

What if the response is closed from the other side? – Tomáš Zato Feb 25 '20 at 11:29
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. – tadman Feb 25 '20 at 17:11
4

res.finished is deprecated, you can use response.writableEnded or request.writableFinished depending what you want. – AndyJRR Feb 25 '20 at 20:31
1

@AndyJRR If this answer is out of date and you know how it works in the current Express it may be worth posting an alternate answer. – tadman Feb 25 '20 at 21:53

2 Answers2