How to display the full help of a command when an error occures?

[electrotype]

Let's say an option is required but is missing. Commander then automatically displays a short "error: required option '--myOption' not specified" message. But what if, in addition to this message, I also want to display the full help of the command? Is this possible?

And, related question:

I do use exitOverride() and a big try/catch block. After parseAsync() has been called on a command with subcommands, is there a way to know what is the subcommand that was actually called? If an error occures and I could know the subcommand in my catch block, I guess I could display the help by myself (using subCommand.outputHelp()).

[shadowspawn]

Hmm, there is not direct support for either.

(Perhaps the CommanderError could include the failing command as a property.)

On a related note, the unknown command error got modified to include a reference to the help.

% fab unknown
error: unknown command 'unknown'. See 'fab --help'.

[shadowspawn]

I think you could display the appropriate help by subclassing and overriding .command to add a command specific .exitOverride. Interested, or too heavy-weight?

[electrotype]

Inspired by your suggestions:

command.exitOverride(err => {
  if (err.code !== 'commander.executeSubCommandAsync') {
    err.command = command;
    throw err;
  } else {
    // Async callback from spawn events, not useful to throw.
  }
});

I then have access to the command in my catch block. Works perfectly!

Thanks.

[shadowspawn]

An answer was worked out, and no further activity in a month. Closing this as resolved.

Feel free to open a new issue if it comes up again, with new information and renewed interest.

[shadowspawn]

Related: .showHelpAfterError() added in prerelease v8.0.0-2 by PR #1534