Nuxt/bin/nuxt-dev

#!/usr/bin/env node
/* eslint-disable no-console */

const _ = require('lodash')
const debug = require('debug')('nuxt:build')
debug.color = 2 // force green color
const fs = require('fs')
const parseArgs = require('minimist')
const { Nuxt, Builder, Utils } = require('..')
const chokidar = require('chokidar')
const path = require('path')
const resolve = path.resolve
const pkg = require(path.join('..', 'package.json'))

const argv = parseArgs(process.argv.slice(2), {
  alias: {
    h: 'help',
    H: 'hostname',
    p: 'port',
    c: 'config-file',
    s: 'spa',
    u: 'universal',
    v: 'version'
  },
  boolean: ['h', 's', 'u', 'v'],
  string: ['H', 'c'],
  default: {
    c: 'nuxt.config.js'
  }
})

if (argv.version) {
  console.log(pkg.version)
  process.exit(0)
}

if (argv.hostname === '') {
  Utils.fatalError('Provided hostname argument has no value')
}

if (argv.help) {
  console.log(`
    Description
      Starts the application in development mode (hot-code reloading, error
      reporting, etc)
    Usage
      $ nuxt dev <dir> -p <port number> -H <hostname>
    Options
      --port, -p          A port number on which to start the application
      --hostname, -H      Hostname on which to start the application
      --spa               Launch in SPA mode
      --universal         Launch in Universal mode (default)
      --config-file, -c   Path to Nuxt.js config file (default: nuxt.config.js)
      --help, -h          Displays this message
  `)
  process.exit(0)
}

const rootDir = resolve(argv._[0] || '.')
const nuxtConfigFile = resolve(rootDir, argv['config-file'])

// Load config once for chokidar
const nuxtConfig = loadNuxtConfig()
_.defaultsDeep(nuxtConfig, { watchers: { chokidar: { ignoreInitial: true } } })

// Start dev
let dev = startDev()
let needToRestart = false

// Start watching for nuxt.config.js changes
chokidar.watch(nuxtConfigFile, nuxtConfig.watchers.chokidar).on('all', () => {
  debug('[nuxt.config.js] changed')
  needToRestart = true

  dev = dev.then(instance => {
    if (needToRestart === false) return instance
    needToRestart = false

    debug('Rebuilding the app...')
    return startDev(instance)
  })
})

function startDev(oldInstance) {
  // Get latest environment variables
  const port =
    argv.port || process.env.PORT || process.env.npm_package_config_nuxt_port
  const host =
    argv.hostname ||
    process.env.HOST ||
    process.env.npm_package_config_nuxt_host

  // Error handler
  const onError = (err, instance) => {
    Utils.printError(err)
    return Promise.resolve(instance) // Wait for next reload
  }

  // Load options
  let options = {}
  try {
    options = loadNuxtConfig()
  } catch (err) {
    return onError(err, oldInstance)
  }

  // Create nuxt and builder instance
  let nuxt
  let builder
  let instance
  try {
    nuxt = new Nuxt(options)
    builder = new Builder(nuxt)
    instance = { nuxt: nuxt, builder: builder }
  } catch (err) {
    return onError(err, instance || oldInstance)
  }

  return (
    Promise.resolve()
      .then(
        () =>
          oldInstance && oldInstance.builder
            ? oldInstance.builder.unwatch()
            : Promise.resolve()
      )
      // Start build
      .then(() => builder.build())
      // Close old nuxt after successful build
      .then(
        () =>
          oldInstance && oldInstance.nuxt
            ? oldInstance.nuxt.close()
            : Promise.resolve()
      )
      // Start listening
      .then(() => nuxt.listen(port, host))
      // Pass new nuxt to watch chain
      .then(() => instance)
      // Handle errors
      .catch(err => onError(err, instance))
  )
}

function loadNuxtConfig() {
  let options = {}

  if (fs.existsSync(nuxtConfigFile)) {
    delete require.cache[nuxtConfigFile]
    options = require(nuxtConfigFile)
  } else if (argv['config-file'] !== 'nuxt.config.js') {
    Utils.fatalError('Could not load config file: ' + argv['config-file'])
  }

  if (typeof options.rootDir !== 'string') {
    options.rootDir = rootDir
  }

  // Force development mode for add hot reloading and watching changes
  options.dev = true

  // Nuxt Mode
  options.mode =
    (argv['spa'] && 'spa') || (argv['universal'] && 'universal') || options.mode

  return options
}