1/**2 * Copyright (c) Meta Platforms, Inc. and affiliates.3 *4 * This source code is licensed under the MIT license found in the5 * LICENSE file in the root directory of this source tree.6 *7 */89'use strict';1011const babelRegister = require('@babel/register');12babelRegister({13  ignore: [/[\\\/](build|server\/server|node_modules)[\\\/]/],14  presets: [['react-app', {runtime: 'automatic'}]],15  plugins: ['@babel/transform-modules-commonjs'],16});1718const express = require('express');19const compress = require('compression');20const {readFileSync} = require('fs');21const path = require('path');22const renderToString = require('./render-to-string');23const renderToStream = require('./render-to-stream');24const renderToBuffer = require('./render-to-buffer');25const {JS_BUNDLE_DELAY} = require('./delays');2627const PORT = process.env.PORT || 4000;28const app = express();2930app.use(compress());31app.get(32  '/',33  handleErrors(async function (req, res) {34    await waitForWebpack();35    renderToStream(req.url, res);36  })37);38app.get(39  '/string',40  handleErrors(async function (req, res) {41    await waitForWebpack();42    renderToString(req.url, res);43  })44);45app.get(46  '/stream',47  handleErrors(async function (req, res) {48    await waitForWebpack();49    renderToStream(req.url, res);50  })51);52app.get(53  '/buffer',54  handleErrors(async function (req, res) {55    await waitForWebpack();56    renderToBuffer(req.url, res);57  })58);59app.use(express.static('build'));60app.use(express.static('public'));6162app63  .listen(PORT, () => {64    console.log(`Listening at ${PORT}...`);65  })66  .on('error', function (error) {67    if (error.syscall !== 'listen') {68      throw error;69    }70    const isPipe = portOrPipe => Number.isNaN(portOrPipe);71    const bind = isPipe(PORT) ? 'Pipe ' + PORT : 'Port ' + PORT;72    switch (error.code) {73      case 'EACCES':74        console.error(bind + ' requires elevated privileges');75        process.exit(1);76        break;77      case 'EADDRINUSE':78        console.error(bind + ' is already in use');79        process.exit(1);80        break;81      default:82        throw error;83    }84  });8586function handleErrors(fn) {87  return async function (req, res, next) {88    try {89      return await fn(req, res);90    } catch (x) {91      next(x);92    }93  };94}9596async function waitForWebpack() {97  while (true) {98    try {99      readFileSync(path.resolve(__dirname, '../build/main.js'));100      return;101    } catch (err) {102      console.log(103        'Could not find webpack build output. Will retry in a second...'104      );105      await new Promise(resolve => setTimeout(resolve, 1000));106    }107  }108}