Refresh input devices when new device is plugin

[elmcapp]

Is there a way to get a list of new midi devices when a new device is plugin. Currently I can only get a list of new midi devices when I run the following function. However I like to know if there is a listener or a way allow new midi device to show without running the function every time a new device is connect. something like a hot load

// Inputs
  WebMidi.inputs.forEach(input => console.log(input.manufacturer, input.name));

[djipco]

To do that, you can listen for the connected event of the WebMidi object. It will be triggered whenever a new device (input or output) is connected:

WebMidi.addListener("connected", e => {
    console.log(e.port.name);
});

There are other such events that might be of interest to you such as portschanged, disabled, disconnected, etc.

P.S. I moved the issue to a conversation since it isn't a problem with the library.

[elmcapp]

I tried
WebMidi.addListener("connected", (e) => {
console.log(e.port.name);
});

it will give me connected devices however if I connect a new device it does not update unless I refresh the script
I also tried portChange and it does not update. To get a refresh list you have to refresh the script

[djipco]

This should work. I know it works for me in the browser. What environment are you in?

[elmcapp]

node js 17.

[elmcapp]

Use it with node and react js

[jdlee022]

I'm also having trouble getting this event to fire using the below code:
WebMidi.addListener("connected", e => { console.log(e.port.name); });

I was assuming that simply plugging in my midi controller and turning it on would get it to trigger, but maybe i misunderstand?

[djipco]

@jdlee022 I can replicate this problem in Node. It looks like the jzz module (which is used to emulate the Web MIDI API in the Node.js environment) is not properly firing statechange events. Let me look into it and get back to you.

[djipco]

I have opened an issue about this with the jzz module team. Let's see what they say...

[djipco]

I have created issue #271 to follow-up on this problem. The author of the jazz-midi module has confirmed the problem. WEBMIDI.js relies on the jazz-midi module for Web MIDI API support on the Node.js platform. Basically, statechange events are not firing as they should in this context.

Thanks for @jdlee022 and @elmcapp for bringing this issue to light.

[rubendax]

Just want to report that listening for 'connected', 'disconnected', and 'portschanged' seems to be working fine now in Node / Electron with webmidi v3.0.21. Plugging in / unplugging a USB MIDI device emits the event as expected for me.

[djipco]

Hmm... interesting. As far as I can tell, the jzz module has not been updated yet (see this issue). Maybe an update to Node actually made the jzz module work properly?! This is odd...

[djipco]

I took some time to look at this once more. It still does not work on my end in Node.js and I'm suspecting the reason it works for you is that Electron uses the browser to execute WEBMIDI.js and not Node.

In version 3.0.25 (just released it), there is a new WebMidi.flavour property that identifies which version of the library is running (cjs, esm or iife). If you had time to install v3.0.25 and print out the value of WebMidi.flavour, it could help me identify if the problem is indeed with the jzz module or not.

It's not always clear what happens under the hood in dual-engine environments such as Electron or NW.js.

[rubendax]

I think you are correct - WEBMIDI.js is being executed in the browser by Electron. WebMidi.flavour prints iife in my setup. Sorry for any confusion that I may have caused.

[djipco]

Thanks for getting back to me so fast! If it prints iife, it definitely means that the browser engine is running it. So, it all makes sense now. By the way, you have nothing to be sorry about. Your help is most welcome. Cheers!