text: /*eslint no-console: 0*/
  'use strict'
  
  // Do this as the first thing so that any code reading it knows the right env.
  process.env.BABEL_ENV = 'development'
  process.env.NODE_ENV = 'development'
  
  // Makes the script crash on unhandled rejections instead of silently
  // ignoring them. In the future, promise rejections that are not handled will
  // terminate the Node.js process with a non-zero exit code.
  process.on('unhandledRejection', err => {
  	throw err
  })
  
  // Ensure environment variables are read.
  require('../config/env')
  
  
  const fs = require('fs')
  const chalk = require('chalk')
  const webpack = require('webpack')
  const WebpackDevServer = require('webpack-dev-server')
  const clearConsole = require('react-dev-utils/clearConsole')
  const checkRequiredFiles = require('react-dev-utils/checkRequiredFiles')
  const {
  	choosePort,
  	createCompiler,
  	prepareProxy,
  	prepareUrls,
  } = require('react-dev-utils/WebpackDevServerUtils')
  const openBrowser = require('react-dev-utils/openBrowser')
  const paths = require('../config/paths')
  const config = require('../config/webpack.config.dev')
  const createDevServerConfig = require('../config/webpackDevServer.config')
  
  const useYarn = fs.existsSync(paths.yarnLockFile)
  const isInteractive = process.stdout.isTTY
  
  // Warn and crash if required files are missing
  if (!checkRequiredFiles([paths.appHtml, paths.appIndexJs])) {
  	process.exit(1)
  }
  
  // Tools like Cloud9 rely on this.
  const DEFAULT_PORT = parseInt(process.env.PORT, 10) || 3000
  const HOST = process.env.HOST || '0.0.0.0'
  
  if (process.env.HOST) {
  	console.log(
  		chalk.cyan(
  			`Attempting to bind to HOST environment variable: ${chalk.yellow(
  				chalk.bold(process.env.HOST)
  			)}`
  		)
  	)
  	console.log(
  		`If this was unintentional, check that you haven't mistakenly set it in your shell.`
  	)
  	console.log(
  		`Learn more here: ${chalk.yellow('http://bit.ly/CRA-advanced-config')}`
  	)
  	console.log()
  }
  
  // We require that you explictly set browsers and do not fall back to
  // browserslist defaults.
  const { checkBrowsers } = require('react-dev-utils/browsersHelper')
  checkBrowsers(paths.appPath, isInteractive)
  	.then(() => {
  		// We attempt to use the default port but if it is busy, we offer the user to
  		// run on a different port. `choosePort()` Promise resolves to the next free port.
  		return choosePort(HOST, DEFAULT_PORT)
  	})
  	.then(port => {
  		if (port == null) {
  			// We have not found a port.
  			return
  		}
  		const protocol = process.env.HTTPS === 'true' ? 'https' : 'http'
  		const appName = require(paths.appPackageJson).name
  		const urls = prepareUrls(protocol, HOST, port)
  		// Create a webpack compiler that is configured with custom messages.
  		const compiler = createCompiler(webpack, config, appName, urls, useYarn)
  		// Load proxy config
  		const proxySetting = require(paths.appPackageJson).proxy
  		const proxyConfig = prepareProxy(proxySetting, paths.appPublic)
  		// Serve webpack assets generated by the compiler over a web server.
  		const serverConfig = createDevServerConfig(
  			proxyConfig,
  			urls.lanUrlForConfig
  		)
  		const devServer = new WebpackDevServer(compiler, serverConfig)
  		// Launch WebpackDevServer.
  		devServer.listen(port, HOST, err => {
  			if (err) {
  				return console.log(err)
  			}
  			if (isInteractive) {
  				clearConsole()
  			}
  			console.log(chalk.cyan('Starting the development server...\n'))
  			openBrowser(urls.localUrlForBrowser)
  		});
  
  		['SIGINT', 'SIGTERM'].forEach(function(sig) {
  			process.on(sig, function() {
  				devServer.close()
  				process.exit()
  			})
  		})
  	})
  	.catch(err => {
  		if (err && err.message) {
  			console.log(err.message)
  		}
  		process.exit(1)
  	})
  