# Yargs

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

![ci](https://github.com/yargs/yargs/workflows/ci/badge.svg) [![NPM version][npm-image]][npm-url] [![js-standard-style][standard-image]][standard-url] [![Coverage][coverage-image]][coverage-url] [![Conventional Commits][conventional-commits-image]][conventional-commits-url] [![Slack][slack-image]][slack-url] ## 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](/docs/api.md). ## Installation Stable version: ```bash npm i yargs ``` Bleeding edge version with the most recent features: ```bash npm i yargs@next ``` ## Usage ### Simple Example ```javascript #!/usr/bin/env node const yargs = require('yargs/yargs') const { hideBin } = require('yargs/helpers') const argv = yargs(hideBin(process.argv)).argv if (argv.ships > 3 && argv.distance < 53.5) { console.log('Plunder more riffiwobbles!') } else { console.log('Retreat from the xupptumblers!') } ``` ```bash $ ./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)`](https://nodejs.org/en/knowledge/command-line/how-to-parse-command-line-arguments/). It has the benefit that it takes into account variations in some environments, e.g., [Electron](https://github.com/electron/electron/issues/4690). ### Complex Example ```javascript #!/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](/docs/typescript.md). ### Deno As of `v16`, `yargs` supports [Deno](https://github.com/denoland/deno): ```typescript 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: ```js 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](/docs/browser.md). ## Community Having problems? want to contribute? join our [community slack](http://devtoolscommunity.herokuapp.com). ## Documentation ### Table of Contents * [Yargs' API](/docs/api.md) * [Examples](/docs/examples.md) * [Parsing Tricks](/docs/tricks.md) * [Stop the Parser](/docs/tricks.md#stop) * [Negating Boolean Arguments](/docs/tricks.md#negate) * [Numbers](/docs/tricks.md#numbers) * [Arrays](/docs/tricks.md#arrays) * [Objects](/docs/tricks.md#objects) * [Quotes](/docs/tricks.md#quotes) * [Advanced Topics](/docs/advanced.md) * [Composing Your App Using Commands](/docs/advanced.md#commands) * [Building Configurable CLI Apps](/docs/advanced.md#configuration) * [Customizing Yargs' Parser](/docs/advanced.md#customizing) * [Bundling yargs](/docs/bundling.md) * [Contributing](/contributing.md) ## Supported Node.js Versions Libraries in this ecosystem make a best effort to track [Node.js' release schedule](https://nodejs.org/en/about/releases/). 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