Node: tty: tty.WriteStream event 'resize' on Windows

[vsemozhetbyt]

• Version: 8.0.0 rc1
• Platform: Windows 7 x64
• Subsystem: tty

Is this event supported on Windows?

The script with this code from the doc exits immediately without launching the event loop. I've tried to modify it like this:

process.stdout.on('resize', () => {
  console.log('screen size has changed!');
  console.log(`${process.stdout.columns}x${process.stdout.rows}`);
});

setInterval(()=>{}, 1000);

and then to resize the console window manually or via the console window properties, but the event handler never fired.

[refack]

Quick answer currently no. It depends on SIGWINCH which comes from [g]libc.
Maybe possible to implement https://stackoverflow.com/questions/10856926/sigwinch-equivalent-on-windows
Definalty need to document

[mscdex]

Perhaps it's supported in WSL?

[vsemozhetbyt]

FWIW, I've tried on Git Bash for Windows with the same result.

[refack]

Do you know if WSL has signals?

[refack]

WSL works for me (with node v7.10 for ubuntu on Windows 10 15063)

But that isn't fair...

[richardlau]

libuv emulates SIGWINCH on Windows: http://docs.libuv.org/en/v1.x/signal.html

SIGWINCH may not always be delivered in a timely manner; libuv will only detect size changes when the cursor is being moved.

[vsemozhetbyt]

@richardlau This variant with a possibility to move cursor also does not work:

process.stdout.on('resize', () => {
  console.log('screen size has changed!');
  console.log(`${process.stdout.columns}x${process.stdout.rows}`);
});

process.stdin.pipe(process.stdout);

And the event handler by itself does not launch event loop, so it is hardly processed.

Could we document this? I am not sure about wording and details.

[Fishrock123]

@vsemozhetbyt sounds like the correct course of action

[refack]

libuv emulates SIGWINCH on Windows: http://docs.libuv.org/en/v1.x/signal.html

@richardlau do we need to move the cursor in a special way? Because the following does not fire. And console.log(`${process.stdout.columns} X ${process.stdout.rows}`); keeps outputing the initial values.

console.log('hello')
console.log(`process.stdout.isTTY? ${process.stdout.isTTY}`)
process.stdout.on('resize', (e) => {
  console.log(e);
  console.log('screen size has changed!');
  console.log(`${process.stdout.columns}x${process.stdout.rows}`);
});

setInterval(() => {
  console.log(`${process.stdout.columns} X ${process.stdout.rows}`);
}, 1000);

[richardlau]

I have no idea; I just remembered that SIGWINCH was specifically mentioned in the libuv docs and quoted the reference.

[bzoz]

The console needs to be in raw mode for this to work (mind, this will not exit after ctrl-c):

process.stdin.setRawMode(true);
process.stdin.on('data', () => {}); // to keep node from exiting
process.stdout.on('resize', (e) => {
  console.log(`${process.stdout.columns}x${process.stdout.rows}`);
});

I guess an doc update should be made.

[vsemozhetbyt]

@bzoz With this code, the event is processed when I change the size via terminal options but is ignored when I change the size manually. This is true for cmd.exe. For the git bash for Windows, manual width change fires the event, height change is ignored.