next.js/bin/next-dev

#!/usr/bin/env node
import { exec } from 'child_process'
import { resolve, join } from 'path'
import parseArgs from 'minimist'
import Server from '../server'
import HotReloader from '../server/hot-reloader'
import webpack from '../server/build/webpack'
import { exists } from 'mz/fs'

const argv = parseArgs(process.argv.slice(2), {
  alias: {
    h: 'help',
    p: 'port'
  },
  boolean: ['h'],
  default: {
    p: 3000
  }
})

const open = url => {
  const openers = { darwin: 'open', win32: 'start' }
  const cmdName = openers[process.platform] || 'xdg-open'
  exec(`${cmdName} ${url}`)
}

const dir = resolve(argv._[0] || '.')

webpack(dir, { hotReload: true })
.then(async (compiler) => {
  const hotReloader = new HotReloader(compiler)
  const srv = new Server({ dir, dev: true, hotReloader })
  await srv.start(argv.port)
  console.log('> Ready on http://localhost:%d', argv.port)

  // Check if pages dir exists and warn if not
  if (!(await exists(join(dir, 'pages')))) {
    if (await exists(join(dir, '..', 'pages'))) {
      console.warn('> No `pages` directory found. Did you mean to run `next` in the parent (`../`) directory?')
    } else {
      console.warn('> Couldn\'t find a `pages` directory. Please create one under the project root')
    }
  }

  if (!/^(false|0)$/i.test(process.env.NEXT_OPEN_BROWSER)) {
    open(`http://localhost:${argv.port}`)
  }
})
.catch((err) => {
  console.error(err)
  exit(1)
})