message: Fix "TypeError: Cannot read property 'split' of undefined" in build script.
diff: @@ -9,7 +9,6 @@ const WebpackDevServer = require("webpack-dev-server");
  const formatWebpackMessages = require("react-dev-utils/formatWebpackMessages");
  const { printFrontendInstructions, createCompiler } = require("./createCompiler");
  const isInteractive = process.stdout.isTTY;
  -const createDevServerConfig = require("../../config/webpackDevServer.config");
  const { prepareProxy, prepareUrls } = require("react-dev-utils/WebpackDevServerUtils");
  async function watchBackend(config) {
  @@ -33,6 +32,7 @@ async function startFrontendDevServer(config, host, port) {
  const proxyConfig = prepareProxy(proxySetting, paths.appPublic);
  // Serve webpack assets generated by the compiler over a web sever.
  + const createDevServerConfig = require("../../config/webpackDevServer.config");
  const serverConfig = createDevServerConfig(
  proxyConfig,
  urls.lanUrlForConfig
  