Update README example for .on('command:*')

[shadowspawn]

Pull Request

Problem

A handler for .on('command:*') is no longer needed just to show an error message, as we do that by default, so would like a new example in the README.

It was suggested we add built-in support to recommend matching command, but do not want to that for now since it would add a dependency: #1015

The example code directly calls process.exit() which is not recommended.

Was:

// error on unknown commands
program.on('command:*', function () {
  console.error('Invalid command: %s\nSee --help for a list of available commands.', program.args.join(' '));
  process.exit(1);
});

Solution

Use actual code for didYouMean as the example.

Follow best practice and do not directly call .exit()

program.on('command:*', function (operands) {
  console.error(`error: unknown command '${operands[0]}'`);
  const availableCommands = program.commands.map(cmd => cmd.name());
  const suggestion = didYouMean(operands[0], availableCommands);
  if (suggestion)
    console.error(`Did you mean '${suggestion}'?`);
  process.exitCode = 1;
});

[abetomo]

👍

[jamesgeorge007]

This would be misleading. Say for instance, a first time user makes use of this code snippet to handle unknown commands ending up with an error saying that didYouMean is not defined.

[shadowspawn]

An alternative I considered was to use a clearly write-your-own routine like:

const availableCommands = program.commands.map(cmd => cmd.name());
const suggestion = myFindBestMatch(operands[0], availableCommands);
console.error(`Did you mean '${suggestion}'?`);
process.exitCode = 1;

Do you think this would be preferable?

[jamesgeorge007]

#1015 (comment)