7 libraries to build Node.js CLI

Last week, I wrote an article about building a Node.js CLI using yargs. I introduced it saying we use cli tools everyday to simplify common tasks in our jobs. I made myself a couple of cli like gitmoji-changelog. It is a changelog generator for gitmoji commit convention.

I would like to share with you a few libraries I used on this project and while contributing to Gatsby. Gatsby is a good source of inspiration, consider contributing to it. I learned a lot while doing it (they give free swag to thank contributions 🤫).

yargs

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It is a library that helps you defining your tool's interface. It also parses arguments for you. The icing on the cake is that yargs generates automatically an help menu.

Here is a simple example that displays a message "Hello [something]" a certain amount of times.

require('yargs') .command('$0 [name]', 'say hello', (yargs) => { yargs .positional('name', { describe: 'hello\'s target', default: 'world' }) .option('times', { alias: 't', type: 'number', default: 1, description: 'number of times to say hello' }) }, (argv) => { for (let i = 0;i < argv.times; i++) { console.log(`Hello ${argv.name}!`) } }) .argv 

Result:

prompts

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A common use case in cli tools is asking user for information. Prompts is a lightweight library based on promises. It implements an exhautive list of question's types.

(async () => { const prompts = require('prompts') const response = await prompts({ type: 'confirm', name: 'value', message: 'Can you confirm?', initial: true }) console.log('Reponse: ', response.value) })() 

Result:

signale

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Standard console API provides only a few methods to display information. Signale comes with 19 built-in methods (logs are prefixed with emojies ❤️)! You can also implements custom loggers.

const signale = require('signale') signale.success('CLI started'); const options = { types: { santa: { badge: '👽', color: 'magenta', label: 'alien', logLevel: 'info' } } } const custom = new signale.Signale(options); custom.santa('E.T go home') signale.complete('Call sent') 

Result:

chalk

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It is a pain in the neck to add style to a cli output. Chalk provides an easy-to-use API to colorize logs. It also supports template literals!

const chalk = require('chalk') console.log(`${chalk.blue('Welcome')} in the activity monitor${chalk.red('!')}`) console.log(chalk.green(`Your computer seems in ${chalk.underline('great')} shape.`)) console.log(` envinfo: CPU: ${chalk.red('90%')} RAM: ${chalk.green('40%')} DISK: ${chalk.yellow('70%')} `) 

Result:

progress

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Another common use case is dealing with asynchronous operations. It is nice to give user a percentage of completion when your cli is doing a heavy computation. Progress is an highly customizable ascii progress bar. It comes with a bunch of options and standard information (percentage, total, estimated completion, ...) to display on the progress bar. You can also add your own information.

const ProgressBar = require('progress') let ticks = 0 const bar = new ProgressBar( 'Rocket launch :bar in :counter', { total: 10, width: 50 }, ) const timer = setInterval(function () { ticks++ bar.tick({ counter: 10 - ticks }) if (bar.complete) { console.log('\n🚀') clearInterval(timer) } }, 100) 

Result:

configstore

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Earlier we saw Prompts to ask user information. It is also nice to store its answer to avoid asking it again and again. Configstore is a library that persists data for you. It stores it in a json file on the user's disk. It handles well the dot notation!

const Configstore = require('configstore') const packageJson = require('../package.json') const config = new Configstore(packageJson.name) config.set('answer', true); console.log('answer:', config.get('answer')); config.set('a.really.deep.config', true); console.log('a.really.deep.config:', config.get('a.really.deep.config')); config.delete('answer'); console.log('answer:', config.get('answer')); 

Result:

envinfo

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As frontend developer I use user-agent to get information about my user device. It helps a lot to reproduce bugs for example. As cli developer you don't have access to this kind of information. envinfo is a library that generates reports that users can provide when opening issues on your project.

(async () => { const envinfo = require('envinfo') const environment = await envinfo.run( { System: ['OS', 'Shell'], Binaries: ['Node', 'Yarn', 'npm'], Utilities: ['Git'], }, { markdown: true } ) console.log(environment) })() 

Result:

Alternatives exist for these libraries but I used these ones and I enjoy working with them. In my opinion, they covers the majority of problems you might encounter while coding cli tools.

Hope it will help 🙌 Happy cli coding!

Feedback is appreciated 🙏 Please tweet me if you have any questions @YvonnickFrin!