Yargs

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

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 <path>       create a client-side Mocha setup at <path>

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]

generate completion scripts for Bash and Zsh for your command
and tons more.

Installation

Using npm for example:

npm i yargs

Usage

Simple Example

#!/usr/bin/env node
import yargs from 'yargs';
import {hideBin} from 'yargs/helpers';
const argv = yargs(hideBin(process.argv)).parse();

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!

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
import yargs from 'yargs';
import {hideBin} from '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.

npm i @types/yargs --save-dev

See usage examples in docs.

Usage in Browser

See examples of using yargs in the browser in docs.

Documentation

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.