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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:
my-program.js serve --port=5000
).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]
Stable version:
npm i yargs
Bleeding edge version with the most recent features:
npm i yargs@next
#!/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!')
}
$ ./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 forprocess.argv.slice(2)
. It has the benefit that it takes into account variations in some environments, e.g., Electron.
#!/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.
yargs has type definitions at @types/yargs.
npm i @types/yargs --save-dev
See usage examples in docs.
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 <files...>', '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()
As of v16
,yargs
supports ESM imports:
import yargs from 'yargs'
import { hideBin } from 'yargs/helpers'
yargs(hideBin(process.argv))
.command('curl <url>', 'fetch the contents of the URL', () => {}, (argv) => {
console.info(argv)
})
.demandCommand(1)
.parse()
See examples of using yargs in the browser in docs.
Having problems? want to contribute? join our community slack.
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.
FAQs
yargs the modern, pirate-themed, successor to optimist.
The npm package yargs receives a total of 71,100,086 weekly downloads. As such, yargs popularity was classified as popular.
We found that yargs demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 2 open source maintainers collaborating on the project.
Did you know?
Socket installs a Github app to automatically flag issues on every pull request and report the health of your dependencies. Find out what is inside your node modules and prevent malicious activity before you update the dependencies.