CLI Building Blocks

1. Create exec' module

2. Parse arguments

3. Interactivity

4. Add spark 🌈

CLI Building Blocks

1. Create exec' module

Development

{
  "name": "cli-chucknorris",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "bin": {
    "chucky": "./bin/index.js"
  },
  "dependencies": {},
  "devDependencies": {},
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC"
}

package.json

#!/usr/bin/env node

magicGoesHere()

./bin/index.js

CLI Building Blocks

2. Parsing Arguments

Development

./myServer [-p | --port] <baseDir>

#!/usr/bin/env node

// you can parse arguments by yourself
console.log(process.argv)

const yargs = require('yargs')

const args = yargs
  .version()
  .help()
  .alias('help', 'h')
  .command('install <moduleName>')
  .option('category')
  .default('category', 'dev')
  .demandOption(['category'])
  .alias('category', 'c')
  .example('chucky --category dev')
  .epilogue('(c) 2018 the wonderful JSHeroes')
  .argv

src: https://github.com/yargs/yargs

CLI Building Blocks

3. Interactivity

Development

src: https://github.com/SBoudrias/Inquirer.js

const inquire = require('inquirer')

return inquire.prompt([
  {
    type: 'confirm',
    name: 'funny',
    message: 'was chuck norris funny?'
  }
])

CLI Building Blocks

4. Spark

Development

src: https://github.com/sindresorhus/ora

src: https://github.com/SamVerschueren/listr

const loader = require('ora')()

loader.start('loading...')
await new Promise(resolve => setTimeout(resolve, 1000))
loader.succeed('ready')


const Listr = require('listr')
const tasks = new Listr([
  {
    title: 'fetch something1',
    task: () => new Promise(resolve => setTimeout(resolve, 1000))
  }
])

return tasks.run()

CLI Building Blocks

Deployment

CLI Building Blocks

1. Manage Configuration

2. Node Versions Compat

Deployment

CLI Building Blocks

Deployment

1. Manage Configuration

CLI Building Blocks

Deployment

1. Manage Configuration

2. Node Versions Compat

Let's Build Something!

LicenseWatch

const LicenseWatch = require('licensewatch')

Blessed

const blessed = require('blessed')
const blessedContrib = require('blessed-contrib')

A Blessed Screen

const screen = blessed.screen()

Vertical Bars

var bar = blessedContrib.bar({
  // set widget label
  label: 'Licenses in Dependencies',

  // center the widget on the screen
  top: 'center',
  left: 0,

  // define vertical bar's layout
  barWidth: 4,
  barSpacing: 15,

  // sets maximum value for bar height otherwise
  // it defaults to 1
  maxHeight: 100
})

Fetch Licenses List

const licenses = new LicenseWatch(
  process.cwd() + '/node_modules/**/package.json'
)

licenses.fetch()

Update Licenses Bar

licenses.on('licensesSummary', (licenses) => {

  const titles = Object.keys(licenses)
  const values = Object.values(licenses)

  screen.append(bar)
  bar.setData({
    titles: titles,
    data: values
  })

  screen.render()
})

Our Licenses CLI Tool