text: 
  
  // 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("react-dev-utils/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 configFactory = require("../config/webpack.config");
  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) || 3100;
  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("https://bit.ly/CRA-advanced-config")}`
    );
    console.log();
  }
  
  // We require that you explicitly 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 config = configFactory("development");
      const protocol = process.env.HTTPS === "true" ? "https" : "http";
      const appName = require(paths.appPackageJson).name;
      const useTypeScript = fs.existsSync(paths.appTsConfig);
      const urls = prepareUrls(protocol, HOST, port);
      const devSocket = {
        warnings: warnings =>
          devServer.sockWrite(devServer.sockets, "warnings", warnings),
        errors: errors => devServer.sockWrite(devServer.sockets, "errors", errors)
      };
      // Create a webpack compiler that is configured with custom messages.
      const compiler = createCompiler({
        appName,
        config,
        devSocket,
        urls,
        useYarn,
        useTypeScript,
        webpack
      });
      // 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();
        }
  
        // We used to support resolving modules according to `NODE_PATH`.
        // This now has been deprecated in favor of jsconfig/tsconfig.json
        // This lets you use absolute paths in imports inside large monorepos:
        if (process.env.NODE_PATH) {
          console.log(
            chalk.yellow(
              "Setting NODE_PATH to resolve modules absolutely has been deprecated in favor of setting baseUrl in jsconfig.json (or tsconfig.json if you are using TypeScript) and will be removed in a future major release of create-react-app."
            )
          );
          console.log();
        }
  
        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);
    });
  