softden2006 / yargs

yargs the modern, pirate-themed successor to optimist.

Yargs

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Yargs be a node.js library fer hearties tryin' ter parse optstrings.

Yargs helps you build interactive command line tools, by parsing arguments and generating an elegant user interface. It gives you:

• commands and (grouped) options (my-program.js serve --port=5000).
• a dynamically generated help menu based on your arguments.

• bash-completion shortcuts for commands and options.
• and tons more.

Installation

npm i yargs --save

Simple Example

#!/usr/bin/env node
const argv = require('yargs').argv

if (argv.ships > 3 && argv.distance < 53.5) {
  console.log('Plunder more riffiwobbles!')
} else {
  console.log('Retreat from the xupptumblers!')
}

$ ./plunder.js --ships=4 --distance=22
Plunder more riffiwobbles!

$ ./plunder.js --ships 12 --distance 98.7
Retreat from the xupptumblers!

Complex Example

#!/usr/bin/env node
require('yargs') // eslint-disable-line
  .command('serve', 'start the server', (yargs) => {
    yargs.option('port', {
      describe: 'port to bind on',
      default: 5000
    })    
  }, (argv) => {
    if (argv.verbose) console.info(`start server on :${argv.port}`)
    serve(argv.port)
  })
  .option('verbose', {
    alias: 'v',
    default: false
  })
  .argv

Run the example above with --help to see the help for the application.

Table of Contents

• Yargs' API
• Examples
• Parsing Tricks
  • Stop the Parser
  • Negating Boolean Arguments
  • Numbers
  • Arrays
  • Objects
• Advanced Topics
  • Composing Your App Using Commands
  • Building Configurable CLI Apps
  • Customizing Yargs' Parser
• Contributing