How to bind events to custom backend service?

#1

I am trying to create a custom USB service using node-usb that fires an event whenever a device connects. The service works fine when I create a function to get a list of connected devices, but I get an error when I try to listen to node-usb’s attach event.

ERROR TypeError: Cannot read property 'apply' of undefined
    at [...]/node_modules/@theia/core/lib/common/event.js:176:33

It looks like my callback does not get passed correctly to the Event. Is my binding wrong? Any ideas?

Here is my code: https://pastebin.com/0xjJnfXD

#2

I could take a look if you could set up a public repo I can clone and build. It is hard to figure out what is causing the TypeError: Cannot read property 'apply' of undefined error from the pastebin snippet.

#3

Ah yeah, that should be much more convenient in many ways. I have set up a stripped down version here: https://github.com/KR155E/theia-test

Build and launch it with yarn all.

1 Like
#4

Forgot to mention: connect any USB device while Theia is running to see the error in the console.

#5

Finally got it working thanks to this topic: How to use Emitter to emit events from backend to frontend :partying_face:

If anybody else is having problems with setting up backend events, here’s my solution: https://github.com/KR155E/theia-test