chore(js): allow uncaughtException plugin to be loaded more than once

[BethanyBerkowitz]

Status

READY

Description

Part of #1163

This PR makes it safe to load the uncaughtException plugin more than once.

• If loaded with enableUncaught true, it will add a listener if one has not already been added
• If loaded with enableUncaught false, it will remove the listener if it exists

However, the client itself still only loads the plugin once, so this PR should not cause any user-facing change in behavior.

Todos

• Tests
• Documentation

Steps to Test or Reproduce

Unit tests should mostly cover it. I also tested it by throwing an uncaught error in one of the example applications. I chose sails, but it could have been express or another node project. The trick is that you have to throw an error in a node application that is not covered by the honeybadger middleware, but also doesn't cause an import to fail entirely. So for example:

Honeybadger.configure({
  apiKey: process.env.HONEYBADGER_API_KEY, 
  enableUncaught: true,
})

setTimeout(() => {
  throw new Error('unhandled err at top-level')
}, 50)

Also tested with enableUncaught: false, which did not send a report (as expected).

I also found that you can't test this in AWS Lambda because the wrapper just wraps the whole thing and calls notify(). So if you throw an uncaught error within your lambda, it’s just going to get reported up to the wrapper.

[subzero10]

This looks good! With this PR, we add support for loading the plugin multiple plugins, but we have yet to reload the plugin when necessary (i.e. when configure is called more than once), right?

[subzero10]

+1 for named functions!

[BethanyBerkowitz]

This looks good! With this PR, we add support for loading the plugin multiple plugins, but we have yet to reload the plugin when necessary (i.e. when configure is called more than once), right?

Correct! There will be a second PR to do this same thing with unhandled rejection (load more than once). Then the 3rd PR will actually reload them when necessary. That way each PR is small and there's only 1 that actually changes the behavior from a user perspective.