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:
- 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.
Stable version:
npm i yargsBleeding edge version with the most recent features:
npm i yargs@next#!/usr/bin/env node
importyargsfrom'yargs';import{hideBin}from'yargs/helpers';constargv=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:
hideBinis 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
importyargsfrom'yargs';import{hideBin}from'yargs/helpers';yargs(hideBin(process.argv)).command('serve [port]','start the server',(yargs)=>{returnyargs.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:
importyargsfrom'https://deno.land/x/yargs@v17.7.2-deno/deno.ts'import{Arguments}from'https://deno.land/x/yargs@v17.7.2-deno/deno-types.ts'yargs(Deno.args).command('download <files...>','download a list of files',(yargs: any)=>{returnyargs.positional('files',{describe: 'a list of files to do something with'})},(argv: Arguments)=>{console.info(argv)}).strictCommands().demandCommand(1).parse()Note: If you use version tags in url then you also have to add
-denoflag on the end, like@17.7.2-deno
See examples of using yargs in the browser in docs.
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.