Yargs

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

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Description

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:

mocha [spec..]
Run tests with Mocha
Commands
  mocha inspect [spec..]  Run tests with Mocha                         [default]
  mocha init        create a client-side Mocha setup at Rules & Behavior
  --allow-uncaught           Allow uncaught errors to propagate        [boolean]
  --async-only, -A           Require all tests to use a callback (async) or
                             return a Promise                          [boolean]

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

Installation

Stable version:

npm i yargs

Bleeding edge version with the most recent features:

npm i yargs@next

Usage

Simple Example

#!/usr/bin/env node
const yargs = require('yargs/yargs')
const { hideBin } = require('yargs/helpers')
const argv = yargs(hideBin(process.argv)).argvif (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!

Note: hideBin is a shorthand for process.argv.slice(2). It has the benefit that it takes into account variations in some environments, e.g., Electron.

Complex Example

#!/usr/bin/env node
const yargs = require('yargs/yargs')
const { hideBin } = require('yargs/helpers')yargs(hideBin(process.argv))
  .command('serve [port]', 'start the server', (yargs) => {
    return yargs
      .positional('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',
    type: 'boolean',
    description: 'Run with verbose logging'
  })
  .parse()

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

Supported Platforms

TypeScript

yargs has type definitions at [@types/yargs][type-definitions].

npm i @types/yargs --save-dev

See usage examples in docs.

Deno

As of v16, yargs supports Deno:

import yargs from 'https://deno.land/x/yargs/deno.ts'
import { Arguments } from 'https://deno.land/x/yargs/deno-types.ts'yargs(Deno.args)
  .command('download ', 'download a list of files', (yargs: any) => {
    return yargs.positional('files', {
      describe: 'a list of files to do something with'
    })
  }, (argv: Arguments) => {
    console.info(argv)
  })
  .strictCommands()
  .demandCommand(1)
  .parse()

ESM

As of v16,yargs supports ESM imports:

import yargs from 'yargs'
import { hideBin } from 'yargs/helpers'yargs(hideBin(process.argv))
  .command('curl ', 'fetch the contents of the URL', () => {}, (argv) => {
    console.info(argv)
  })
  .demandCommand(1)
  .parse()

Usage in Browser

See examples of using yargs in the browser in docs.

Community

Having problems? want to contribute? join our community slack.

Documentation

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

Supported Node.js Versions

Libraries in this ecosystem make a best effort to track Node.js' release schedule. Here's [a post on why we think this is important](https://medium.com/the-node-js-collection/maintainers-should-consider-following-node-js-release-schedule-ab08ed4de71a).

[npm-url]: https://www.npmjs.com/package/yargs [npm-image]: https://img.shields.io/npm/v/yargs.svg [standard-image]: https://img.shields.io/badge/code%20style-standard-brightgreen.svg [standard-url]: http://standardjs.com/ [conventional-commits-image]: https://img.shields.io/badge/Conventional%20Commits-1.0.0-yellow.svg [conventional-commits-url]: https://conventionalcommits.org/ [slack-image]: http://devtoolscommunity.herokuapp.com/badge.svg [slack-url]: http://devtoolscommunity.herokuapp.com [type-definitions]: https://github.com/DefinitelyTyped/DefinitelyTyped/tree/master/types/yargs [coverage-image]: https://img.shields.io/nycrc/yargs/yargs [coverage-url]: https://github.com/yargs/yargs/blob/main/.nycrc

📄 README.md