Nuxt/bin/nuxt-dev

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

// Show logs
process.env.DEBUG = process.env.DEBUG || 'nuxt:*'

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 } = 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 === '') {
  console.error(`> Provided hostname argument has no value`)
  process.exit(1)
}

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) => {
    debug('Error while reloading [nuxt.config.js]', 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') {
    console.error(`> Could not load config file ${argv['config-file']}`)
    process.exit(1)
  }

  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
}