How to show help/usage message on default run of cliffy CLI

[grempe]

I'm creating a new CLI which I'd like to have display the top level help content when the cli is run with no commands or flags. Right now I'm just console.log() a statement that suggests they try to re-run with the --help command. This is not a very satisfying user experience though.

The same applies for sub-commands that the user runs with no commands or flags.

As I understand it I'd need to implement an .action() on the top level command which would call a function to show the same help as I see with --help but I can't seem to find what function I should call to display the help.

Here is an example of what I'm trying to achieve:

import { Command } from "https://deno.land/x/cliffy@v0.18.2/command/mod.ts";
import { HelpCommand } from "https://deno.land/x/cliffy@v0.18.2/command/help/mod.ts";

// Question : how to get both of these commands to print the help?
// deno run helpme.ts
// deno run helpme.ts --help
//
// And these also:
// deno run helpme.ts subcommand
// deno run helpme.ts subcommand --help

const subcommand = new Command()
  .description("HelpMe Demo Sub-Command")
  .action(() => {
    console.log(`How can I display the same output as 'deno run helpme.ts subcommand --help' here?`)
    Deno.exit(0);
  });

const cmd = new Command()
  .name("helpme")
  .version("0.0.0")
  .description("HelpMe Demo")
  .action(() => {
    console.log(`How can I display the same output as 'deno run helpme.ts --help' here?`)
    Deno.exit(0);
  })
  .command("subcommand", subcommand)
  .command("help", new HelpCommand().global());

try {
  cmd.parse(Deno.args);
} catch (error) {
  console.error("Error: ", error.message);
  Deno.exit(1);
}

Thanks!

[c4spar]

Hi @grempe,

you can use cmd.showHelp(). It prints the help text to stdout and there is also a .getHelp() method which returns the help text as string.

[grempe]

Thanks for the quick response. That is exactly what I was looking for.

subcommand.showHelp() also worked as expected to show default help for the subcommand with no args.

I did just go through the docs again to see if I could find this documented. I only found:

You can also override the help output with the .help() method. This overrides the output of the .getHelp() and .showHelp() method's which is used by the -h and --help option and the help command. The help handler will be used for each command, but can be overridden by child commands.

This text didn't make it clear that this is another way to use .showHelp(). Perhaps this case could be documented, or an example created as I think this is a fairly common way to display usage in CLI's.

Thanks!

[c4spar]

Yeah that's true, the documentation is lacking some information. Will update the documentation soon. I'm also planning to build a new website with a better structured documentation.

[callumgare]

The docs are still not very clear about this so as a heads up for future readers here's a code snippit:

import { Command } from "https://deno.land/x/cliffy@v1.0.0-rc.4/command/mod.ts";
import subCommand from "./commands/sub-command.ts";
import denoConfig from "./deno.json" with { type: "json" };

export default new Command()
  .name("name-of-command")
  .version(denoConfig.version)
  .description("Description of command")
  // Note: this .action() call seems to need to be before any .command() calls otherwise it's 
  // silently not run (at least that was the case for me).
  .action(function () {
    this.showHelp();
  })
  .command("sub-command", subCommand)
  .parse(Deno.args);

[c4spar]

Note: this .action() call seems to need to be before any .command() calls otherwise it's silently not run (at least that was the case for me).

@callumgare if you call the .action() method after .command("sub-command", subCommand), then the action is registered to the sub-command command and not to the main command.

[callumgare]

Ahh, good to know. Ta :)

[hojongs]

I had the same issue and this discussion solved my issue! Very helpful!