text: /* eslint-disable no-console */
  /* eslint-disable strict */
  '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);
      });
  