execa
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sindresorhus
Stdio `tap` option
For stderr and stdout the choice between inherit and pipe, has tradeoffs.
Specifically, if you choose inherit, you loose the ability to observe the stream, it's piped straight to the parents stdout/stderr.
I propose we add a tap option. It will be converted internally to the pipe option, but we will grab the pipe, split it into two streams, one stream we pipe directly to stdout/stderr, the other we make available for observation.
Yes! I've always wanted this 😀
That also means you can do use execa() with inherit and get it written directly console, while still getting the stdout/stderr in the promise.
One downside with piping vs inherit: You lose the tty support.
We fake tty for forked processes in AVA. We could reimplement that for execa, but it involves some magic and would only work for Node sources. Maybe opt-in via an option?
Maybe opt-in via an option?
👍 You should make the fake TTY thing in AVA a reusable module we can use here too.
If only Node.js had PTY support...
(tl;dr It would let us pretend to be a terminal when spawning a child process).
There is pty.js - I've used it before and it works. It's got a native component though.
Maybe we could try incorporating that as an optional/peer dependency. If they try to fork a non-node module, it tries to require it (and if it fails it fails - give them a decent error message explaining pty.js is required to make non-node executables work).
Or maybe that is too much effort for what may be a niche case.
There is pty.js - I've used it before and it works.
I'm aware. I've used it too.
It's got a native component though.
That's why it's not a solution for me. Native dependencies are too much hassle.
Or maybe that is too much effort for what may be a niche case.
Yeah. Not worth it, and would be weird with varying behavior. I'd rather see it builtin in Node.js, and I'm planning to open a ticket convincing them when I have time.
Done in #643: one can now use stdout: ['inherit', 'pipe'] to get that behavior. This works also with stderr and stdin.
