Feature request: option to show usage when no args given (and/or on-demand)

[jrr]

In addition to showing usage behind a help flag like -h, I'd like to show it when the user hasn't supplied any arguments at all.

I managed to achieve it like this:

    help: {
      type: Boolean,
      optional: true,
      alias: "h",
      description: "Prints this usage guide",
      defaultValue: process.argv.length <= 2, // show help when the user supplies no args
    },

..but it'd be nice to have this as a first-class feature.

Idea 1: an option to show help when given no arguments

I guess this would belong in ParseOptions. Maybe something like showHelpWhenNoArguments?

    {
        helpArg: 'help',
        headerContentSections: [{ header: 'My Example Config', content: 'Thanks for using Our Awesome Library' }],
        footerContentSections: [{ header: 'Footer', content: `Copyright: Big Faceless Corp. inc.` }],
        showHelpWhenNoArguments: true // <--
    },

Idea 2: the ability to display help on-demand at any time

A more general solution would be a way to programmatically invoke the help screen, so I can choose to display it based on the parsed result:

const args = parse<CLIArguments>(...)
// ...
if (_.isEmpty(args)) {
  // printHelp()
}

It might be tricky to design the API for that, though, since it requires access to information that is consumed by parse(). One way could be to expose more things on args:

const args = parse<CLIArguments>(...)
// ...
if(args.noArgumentsGiven){
   args.printHelp();
}

---

Are either of these already possible? Do they sound useful?

[Roaders]

I think the fixes I have submitted support either of your requested use cases. Take a look and let me know if you have any issues.

[jrr]

Wow, that was fast, thanks!

The thing is that I don't have any required arguments, they're all optional. (so I don't think the new options hideMissingArgMessages / showHelpWhenArgsMissing / helpWhenArgMissingHeader will help with use case 1 above)

The new addCommandLineResults option is great, though, and covers idea 2.

Here's what I'm doing now, instead of checking process.argv.length:

  if (_.isEqual(Object.keys(args), ["_commandLineResults"])) {
    args._commandLineResults.printHelp();
  }

(in other words, "when the user didn't supply any arguments at all, print the help")

[Roaders]

I think that the easiest way for you to find out if any arguments at all were passed is just to use process.argv.