concat stream not emitting "end" event

[Benjamín Eidelman]

I might be missing something but I'm trying a simple stream concat of 2 streams,
and noticed that while each stream emits the "end" event, the concat result doesn't.

Reproduction Steps:

var highland = require("highland");
(function() {
s1 = highland(['1', '2', '3']), s2 = highland(['4', '5', '6']), s3 = s1.concat(s2);
const log = s => process.stdout.write(` [${s}] `);
s1.on('end', function() { log('s1 ended') });
s2.on('end', function() { log('s2 ended') });
s3.on('end', function() { log('s3 ended') });
s3.map(n => `[${n}]`).pipe(process.stdout);
})();

Outputs:
[1][2][3] [s1 ended] [4][5][6] [s2 ended] undefined
Expected:
[s3 ended] to print to console too.

ps: I noticed that if I add another transform at the end ( s4 = s3.map(....); s4.on('end', ...)), that stream does emit "end".

[Victor Vu]

This sounds like a bug. The "undefined" part of the output too. I'm travelling right now, but I'll try to take a look in a few days. Does using stream.observe().done(...) work as a workaround for the 'end' event? Using events directly isn't really recommended, since they're not on a well-tested code path.

…

On Sun, Jul 8, 2018, 6:35 PM Benjamín Eidelman ***@***.***> wrote: I might be missing something but I'm trying a simple stream concat of 2 streams, and noticed that while each stream emits the "end" event, the concat result doesn't. Reproduction Steps: var highland = require("highland"); (function() { s1 = highland(['1', '2', '3']), s2 = highland(['4', '5', '6']), s3 = s1.concat(s2);const log = s => process.stdout.write(` [${s}] `);s1.on('end', function() { log('s1 ended') });s2.on('end', function() { log('s2 ended') });s3.on('end', function() { log('s3 ended') });s3.map(n => `[${n}]`).pipe(process.stdout); })(); Outputs: [1][2][3] [s1 ended] [4][5][6] [s2 ended] undefined Expected: [s3 ended] to print to console too. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#653>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AGIyZTj0ZhJB1KKfLC1EDySHwGsJEHB_ks5uErNHgaJpZM4VG9nJ> .

[Benjamín Eidelman]

thanks!

just tried:

var highland = require("highland");
(function() {
s1 = highland(['1', '2', '3']), s2 = highland(['4', '5', '6']), s3 = s1.concat(s2);
const log = s => process.stdout.write(` [${s}] `);
s1.observe().done(function() { log('s1 done') });
s2.observe().done(function() { log('s2 done') });
s3.observe().done(function() { log('s3 done') });
s3.map(n => `[${n}]`).pipe(process.stdout);
})();

but same results

[Victor Vu]

Took a look at this on my phone while waiting at the airport. The reason why observe doesn't work is this todo: https://github.com/caolan/highland/blob/2.x/lib/index.js#L1367 The reason why on('end') doesn't work is because of an different but related bug where we don't copy the EventEmitter handlers. I suspect the 'data' and 'error' events don't work either when combined with stream redirection.

…

On Sun, Jul 8, 2018, 8:20 PM Benjamín Eidelman ***@***.***> wrote: thanks! just tried: var highland = require("highland"); (function() { s1 = highland(['1', '2', '3']), s2 = highland(['4', '5', '6']), s3 = s1.concat(s2);const log = s => process.stdout.write(` [${s}] `);s1.observe().done(function() { log('s1 done') });s2.observe().done(function() { log('s2 done') });s3.observe().done(function() { log('s3 done') });s3.map(n => `[${n}]`).pipe(process.stdout); })(); but same results — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#653 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AGIyZWNg0N89VI3BtrXdt_t1GVBgdkH9ks5uEswRgaJpZM4VG9nJ> .