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CLI tool in Nue.Js source code.

In this article, we will review the how the CLI tool is written in Nue.js source code. Nue.js CLI tool supports the below listed commands: Help Serve Build Create Init We will review Help, Init commands to understand the underlying pattern. Help command Let’s find out how help is printed to CLI. At line 126-133 in packages/nuejs/src/cli.js, you will find the below code: // Only run main when called as real CLI if (esMain(import.meta)) { const args = getArgs(process.argv.slice(2)) // help if (args.help) { await printHelp() // version } printHelp() printHelp() is defined in the same cli.js file and has the below code: async function printHelp() { const { getHelp } = await import('./cli-help.js') console.info(getHelp()) } Check out the cli-help.js it contains the below code: #!/usr/bin/env bun import { esMain, log, colors, version, getEngine, openUrl } from './util.js' // [-npe] --> [-n, -p, -e] export function expandArgs(args) { const arr = [] args.forEach(arg => { if (arg[0] == '-' && arg[1] != '-' && arg[2]) { arg.slice(1).split('').forEach(el => arr.push('-' + el)) } else { arr.push(arg) } }) return arr } // TODO: tests export function getArgs(argv) { const commands = ['serve', 'build', 'init', 'create', 'docs'] const args = { paths: [], root: null } let opt expandArgs(argv).forEach((arg) => { // skip if (arg == '--') { // test suite } else if (arg.endsWith('.test.js')) { args.test = true // command } else if (!args.cmd && commands.includes(arg)) { args.cmd = arg // options } else if (!opt && arg[0] == '-') { // booleans if (['-p', '--production'].includes(arg)) args.is_prod = true else if (['-v', '--version'].includes(arg) && !args.cmd) args.version = true else if (['-n', '--dry-run'].includes(arg)) args.dryrun = true else if (['-h', '--help'].includes(arg)) args.help = true else if (['-v', '--verbose'].includes(arg)) args.verbose = true else if (['-b', '--esbuild'].includes(arg)) args.esbuild = true else if (['-l', '--lcss'].includes(arg)) args.lcss = true else if (['-d', '--deploy'].includes(arg)) args.deploy = args.is_prod = true else if (['-I', '--incremental'].includes(arg)) args.incremental = true else if (['-o', '--open'].includes(arg)) args.open = true // string values else if (['-e', '--environment'].includes(arg)) opt = 'env' else if (['-r', '--root'].includes(arg)) opt = 'root' else if (['-P', '--port'].includes(arg)) opt = 'port' else if (['-B', '--base'].includes(arg)) opt = 'base' // bad options else throw `Unknown option: "${arg}"` } else if (arg && arg[0] != '-') { if (opt) { args[opt] = opt == 'port' ? Number(arg) : arg // Number(alphabetic characters) is falsy. Check if port is really set: if (opt != 'port' || (opt == 'port' && args.port)) opt = null } else args.paths.push(arg) } else if (opt) throw `"${opt}" option is not set` }) if (opt) throw `"${opt}" option is not set` return args } async function printHelp() { const { getHelp } = await import('./cli-help.js') console.info(getHelp()) } async function printVersion() { log(`Nue ${version} ${colors.green('•')} ${getEngine()}`) } async function runCommand(args) { if (args.cmd == 'docs') return openUrl('https://nuejs.org/docs/') const { createKit } = await import('./nuekit.js') const { cmd = 'serve', dryrun, deploy, root = null, port } = args const init = cmd == 'init' if (!root) args.root = '.' // ensure root is unset for create, if not set manually console.info('') await printVersion() args.nuekit_version = version // create nue if (cmd == 'create') { const { create } = await import('./create.js') return await create({ ...args, root, port }) } const nue = await createKit(args) if (!nue) return if (args.open) openUrl(`http://localhost:${nue.port}/`) // deployer (private repo) const { deploy: deployer } = deploy ? await import('nue-deployer') : {} // build if (init) { await nue.init(true) if (deploy) await deployer({ root: nue.dist, init: true }) } else if (dryrun || deploy || args.paths[0] || cmd == 'build') { const paths = await nue.build(args.paths) if (!dryrun && deploy && paths[0]) await deployer({ paths, root: nue.dist, init }) // serve } else { await nue.serve() } } // Only run main when called as real CLI if (esMain(import.meta)) { const args = getArgs(process.argv.slice(2)) // help if (args.help) { await printHelp() // version } else if (args.version) { await printVersion() // command } else if (!args.test) { try { await runCommand(args) } catch (e) { console.info(e) } } } Init command At line 90 in cli.js, there is this below ch

Apr 8, 2025 - 04:44
 0
CLI tool in Nue.Js source code.

In this article, we will review the how the CLI tool is written in Nue.js source code.

Image description

Nue.js CLI tool supports the below listed commands:

  1. Help

  2. Serve

  3. Build

  4. Create

  5. Init

We will review Help, Init commands to understand the underlying pattern.

Help command

Let’s find out how help is printed to CLI. At line 126-133 in packages/nuejs/src/cli.js, you will find the below code:

// Only run main when called as real CLI
if (esMain(import.meta)) {

  const args = getArgs(process.argv.slice(2))

  // help
  if (args.help) {
    await printHelp()

    // version
  }

printHelp()

printHelp() is defined in the same cli.js file and has the below code:

async function printHelp() {
  const { getHelp } = await import('./cli-help.js')
  console.info(getHelp())
}

Check out the cli-help.js it contains the below code:


#!/usr/bin/env bun

import { esMain, log, colors, version, getEngine, openUrl } from './util.js'


// [-npe] --> [-n, -p, -e]
export function expandArgs(args) {
  const arr = []
  args.forEach(arg => {
    if (arg[0] == '-' && arg[1] != '-' && arg[2]) {
      arg.slice(1).split('').forEach(el => arr.push('-' + el))
    } else {
      arr.push(arg)
    }
  })
  return arr
}

// TODO: tests
export function getArgs(argv) {
  const commands = ['serve', 'build', 'init', 'create', 'docs']
  const args = { paths: [], root: null }
  let opt

  expandArgs(argv).forEach((arg) => {
    // skip
    if (arg == '--') {

      // test suite
    } else if (arg.endsWith('.test.js')) {
      args.test = true

      // command
    } else if (!args.cmd && commands.includes(arg)) {
      args.cmd = arg

      // options
    } else if (!opt && arg[0] == '-') {

      // booleans
      if (['-p', '--production'].includes(arg)) args.is_prod = true
      else if (['-v', '--version'].includes(arg) && !args.cmd) args.version = true
      else if (['-n', '--dry-run'].includes(arg)) args.dryrun = true
      else if (['-h', '--help'].includes(arg)) args.help = true
      else if (['-v', '--verbose'].includes(arg)) args.verbose = true
      else if (['-b', '--esbuild'].includes(arg)) args.esbuild = true
      else if (['-l', '--lcss'].includes(arg)) args.lcss = true
      else if (['-d', '--deploy'].includes(arg)) args.deploy = args.is_prod = true
      else if (['-I', '--incremental'].includes(arg)) args.incremental = true
      else if (['-o', '--open'].includes(arg)) args.open = true

      // string values
      else if (['-e', '--environment'].includes(arg)) opt = 'env'
      else if (['-r', '--root'].includes(arg)) opt = 'root'
      else if (['-P', '--port'].includes(arg)) opt = 'port'
      else if (['-B', '--base'].includes(arg)) opt = 'base'

      // bad options
      else throw `Unknown option: "${arg}"`

    } else if (arg && arg[0] != '-') {
      if (opt) {
        args[opt] = opt == 'port' ? Number(arg) : arg
        // Number(alphabetic characters) is falsy. Check if port is really set:
        if (opt != 'port' || (opt == 'port' && args.port)) opt = null
      }
      else args.paths.push(arg)
    } else if (opt) throw `"${opt}" option is not set`
  })

  if (opt) throw `"${opt}" option is not set`

  return args
}

async function printHelp() {
  const { getHelp } = await import('./cli-help.js')
  console.info(getHelp())
}

async function printVersion() {
  log(`Nue ${version} ${colors.green('•')} ${getEngine()}`)
}

async function runCommand(args) {
  if (args.cmd == 'docs') return openUrl('https://nuejs.org/docs/')

  const { createKit } = await import('./nuekit.js')
  const { cmd = 'serve', dryrun, deploy, root = null, port } = args
  const init = cmd == 'init'

  if (!root) args.root = '.' // ensure root is unset for create, if not set manually

  console.info('')
  await printVersion()
  args.nuekit_version = version

  // create nue
  if (cmd == 'create') {
    const { create } = await import('./create.js')
    return await create({ ...args, root, port })
  }

  const nue = await createKit(args)
  if (!nue) return
  if (args.open) openUrl(`http://localhost:${nue.port}/`)

  // deployer (private repo)
  const { deploy: deployer } = deploy ? await import('nue-deployer') : {}

  // build
  if (init) {
    await nue.init(true)
    if (deploy) await deployer({ root: nue.dist, init: true })

  } else if (dryrun || deploy || args.paths[0] || cmd == 'build') {
    const paths = await nue.build(args.paths)
    if (!dryrun && deploy && paths[0]) await deployer({ paths, root: nue.dist, init })

    // serve
  } else {
    await nue.serve()
  }
}

// Only run main when called as real CLI
if (esMain(import.meta)) {

  const args = getArgs(process.argv.slice(2))

  // help
  if (args.help) {
    await printHelp()

    // version
  } else if (args.version) {
    await printVersion()

    // command
  } else if (!args.test) {
    try {
      await runCommand(args)
    } catch (e) {
      console.info(e)
    }
  }
}

Init command

At line 90 in cli.js, there is this below check:

async function runCommand(args) {
  if (args.cmd == 'docs') return openUrl('https://nuejs.org/docs/')

  const { createKit } = await import('./nuekit.js')
  const { cmd = 'serve', dryrun, deploy, root = null, port } = args
  const init = cmd == 'init'

At line 112 in the cli.js, you will find the below code:

if (init) {
    await nue.init(true)
    if (deploy) await deployer({ root: nue.dist, init: true })
}

nue.init? where is that coming from? you will see this below code at line 104

  const nue = await createKit(args)

createKit

createKit is exported from nuekit.js and has 383 LOC at the time of writing this article. Since we are interested in init, I searched for “init” in this nuekit.js file and found the below code:

async function init(force) {
    await initNueDir({ dist, is_dev, esbuild, force })
}

initNueDir is imported from a file named init.js. Similarly I saw create.js.

About me:

Hey, my name is Ramu Narasinga. I study large open-source projects and create content about their codebase architecture and best practices, sharing it through articles, videos.

I am open to work on interesting projects. Send me an email at ramu.narasinga@gmail.com

My Github — https://github.com/ramu-narasinga

My website — https://ramunarasinga.com

My Youtube channel — https://www.youtube.com/@ramu-narasinga

Learning platform — https://thinkthroo.com

Codebase Architecture — https://app.thinkthroo.com/architecture

Best practices — https://app.thinkthroo.com/best-practices

Production-grade projects — https://app.thinkthroo.com/production-grade-projects

References:

  1. https://github.com/nuejs/nue/blob/master/packages/nuekit/src/cli.js

  2. https://github.com/nuejs/nue/blob/master/packages/nuekit/package.json#L14

  3. https://nuejs.org/docs/command-line-interface.html

  4. https://github.com/nuejs/nue/blob/master/packages/nuekit/src/cli.js#L76

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