fix: Detect and kill browser process when launcher process is being used

[birtles]

Fixes #101.

[BrennanConroy]

I'm unable to use this package after this change.
I'm getting: TypeError: this.on is not a function

Changing this to:

process.on('exit', function () {
  if (browserProcessPid) {
    try {
      process.kill(browserProcessPid)
    } catch (e) {
  }
})

fixes it locally.

[birtles]

Oh, I'm not sure what's going on there. I don't recall how this all fits together, but I thought it should define the on method here and it worked for me previously.

I'd like to understand what changed or what is going wrong. I don't suppose you're using a more recent version of karma than 4.2.0, for example?

[BrennanConroy]

I'm using karma 3.1.4 and tried 4.4.1, both had the same issue.

[BrennanConroy]

this.on is valid inside the _start function, but not valid outside of that function. No idea why, but would it be possible to modify this and release a new version?

[johnjbarton]

@BrennanConroy Please open an issue with steps to reproduce your problem.

[BrennanConroy]

Figured it out. We have some code to check if the browser exists before putting it in the karma config, and instead of using FirefoxHeadlessBrowser.prototype we were creating an instance and passing an empty function for the base launcher. Sorry for the false alarm 😄