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:
`bash
npm i yargs
`

Bleeding edge version with the most recent features:
`bash
npm i yargs@next
`

Usage

$3

`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). It has the benefit that it takes into account variations in some environments, e.g., Electron.

$3

`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

$3

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

`
npm i @types/yargs --save-dev
`

See usage examples in docs.

$3

As of v16, yargs supports 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()
`

$3

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()
``

$3

See examples of using yargs in the browser in docs.

Community

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

Documentation

$3

* 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.

[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/main/types/yargs
[coverage-image]: https://img.shields.io/nycrc/yargs/yargs
[coverage-url]: https://github.com/yargs/yargs/blob/main/.nycrc