Sywac NPM | npm.io

So you want a CLI...

A better CLI framework, made for the ES2015 era.

Visit http://sywac.io for detailed documentation. NOTE! The docs site is still under construction.

Feature Highlights

Single package install
Asynchronous parsing, validation, and command execution
Type-based argument parsing
Plug in your own types or override/extend the built-in ones
Support for simple CLIs or complex nested command trees
First-class support for positional arguments, with or without commands
Flexible auto-generated help content
Support for ANSI styles/colors (we recommend chalk)
Define styles/colors inline or decorate content with style hooks
Coherent API
Parse strings as easily as process.argv
Supports concurrent parsing, safe for chatbots or other server-side apps

Quick Start Guide

First install sywac from npm:

$ npm install --save sywac

Then create a cli.js file with code similar to this:

#!/usr/bin/env node

const sywac = require('sywac')

async function main () {
  const argv = await sywac
    .positional('<string>', { paramsDesc: 'A required string argument' })
    .boolean('-b, --bool', { desc: 'A boolean option' })
    .number('-n, --num <number>', { desc: 'A number option' })
    .help('-h, --help')
    .version('-v, --version')
    .showHelpByDefault()
    .outputSettings({ maxWidth: 75 })
    .parseAndExit()
  console.log(JSON.stringify(argv, null, 2))
}

main()

Make the cli.js file executable:

$ chmod +x cli.js

And set up cli.js as the "bin" field in package.json:

{
  "name": "example",
  "version": "0.1.0",
  "bin": "cli.js"
}

Then test it out. Without any arguments, it will print the help text.

$ ./cli.js
Usage: cli <string> [options]

Arguments:
  <string>  A required string argument                  [required] [string]

Options:
  -b, --bool          A boolean option                            [boolean]
  -n, --num <number>  A number option                              [number]
  -h, --help          Show help                  [commands: help] [boolean]
  -v, --version       Show version number     [commands: version] [boolean]

Let's try passing some arguments:

$ ./cli.js hello -b -n 42
{
  "_": [],
  "string": "hello",
  "b": true,
  "bool": true,
  "n": 42,
  "num": 42,
  "h": false,
  "help": false,
  "v": false,
  "version": false
}

What happens if we pass flags without a string argument?

$ ./cli.js --bool
Usage: cli <string> [options]

Arguments:
  <string>  A required string argument                  [required] [string]

Options:
  -b, --bool          A boolean option                            [boolean]
  -n, --num <number>  A number option                              [number]
  -h, --help          Show help                  [commands: help] [boolean]
  -v, --version       Show version number     [commands: version] [boolean]

Missing required argument: string

Validation failed and sywac printed the help text with an error message. Let's check the exit code of that last run: