"error" event handlers require the error to be handled twice

[Holger-Will]

What version of standard?

12.0.1

What operating system, Node.js, and npm version?

linux, node 8.4.0 (my min version), npm 6.9.0

What did you expect to happen?

when using an event bases error handler:

this.port.on('error', err => {
  node.warn('an error occurred')
})

i get Expected error to be handled
but when i use

this.port.on('error', err => {
  if (err) {
    node.warn('an error occurred')
  }
})

everything is fine.

this seems superfluous to me. The error handler is only called if there is an error, so err is always an error object.

I think you should not be required to check for the error object in this case.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs.

[feross]

If you name the variable err then you should use it. You don't need to include it in an if block, though. You can use it in the warning message that you print, like this:

this.port.on('error', err => {
  node.warn('an error occurred ' + err.message)
})

If you don't want to use the error, then don't include an err argument. Do this:

this.port.on('error', () => {
  node.warn('an error occurred')
})