Catch is a special type of Command object, and is returned after vorpal.catch is used.

Catch is an extension of the Command object, and is returned after vorpal.catch is used. A catch instance inherits all vorpal.command methods, with the exception that it is only called when no other commands have been matched, instead of the automated help.

• .catch

The .catch method is identical to vorpal.command, with the exception that only parameters are passed in. When the user types an invalid command, the .catch method's .action method is fired.

There can only be one .catch method defined in an application.

vorpal
  .catch('[words...]', 'Catches incorrect commands')
  .action(function (args, cb) {
    this.log(args.words.join(' ') + ' is not a valid command.');
    cb();
  });

This is excellent for applications that are expected to accept any type of command, such as a CLI app for doing google searches.