start.js 3.7 KB

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  1. 'use strict';
  2. // Do this as the first thing so that any code reading it knows the right env.
  3. process.env.BABEL_ENV = 'development';
  4. process.env.NODE_ENV = 'development';
  5. // Makes the script crash on unhandled rejections instead of silently
  6. // ignoring them. In the future, promise rejections that are not handled will
  7. // terminate the Node.js process with a non-zero exit code.
  8. process.on('unhandledRejection', err => {
  9. throw err;
  10. });
  11. // Ensure environment variables are read.
  12. require('../config/env');
  13. const fs = require('fs');
  14. const chalk = require('chalk');
  15. const webpack = require('webpack');
  16. const WebpackDevServer = require('webpack-dev-server');
  17. const clearConsole = require('react-dev-utils/clearConsole');
  18. const checkRequiredFiles = require('react-dev-utils/checkRequiredFiles');
  19. const {
  20. choosePort,
  21. createCompiler,
  22. prepareProxy,
  23. prepareUrls,
  24. } = require('react-dev-utils/WebpackDevServerUtils');
  25. const openBrowser = require('react-dev-utils/openBrowser');
  26. const paths = require('../config/paths');
  27. const config = require('../config/webpack.config.dev');
  28. const createDevServerConfig = require('../config/webpackDevServer.config');
  29. const useYarn = fs.existsSync(paths.yarnLockFile);
  30. const isInteractive = process.stdout.isTTY;
  31. // Warn and crash if required files are missing
  32. if (!checkRequiredFiles([paths.appHtml, paths.appIndexJs])) {
  33. process.exit(1);
  34. }
  35. // Tools like Cloud9 rely on this.
  36. const DEFAULT_PORT = parseInt(process.env.PORT, 10) || 3000;
  37. const HOST = process.env.HOST || '0.0.0.0';
  38. if (process.env.HOST) {
  39. console.log(
  40. chalk.cyan(
  41. `Attempting to bind to HOST environment variable: ${chalk.yellow(
  42. chalk.bold(process.env.HOST)
  43. )}`
  44. )
  45. );
  46. console.log(
  47. `If this was unintentional, check that you haven't mistakenly set it in your shell.`
  48. );
  49. console.log(
  50. `Learn more here: ${chalk.yellow('http://bit.ly/CRA-advanced-config')}`
  51. );
  52. console.log();
  53. }
  54. // We require that you explictly set browsers and do not fall back to
  55. // browserslist defaults.
  56. const { checkBrowsers } = require('react-dev-utils/browsersHelper');
  57. checkBrowsers(paths.appPath, isInteractive)
  58. .then(() => {
  59. // We attempt to use the default port but if it is busy, we offer the user to
  60. // run on a different port. `choosePort()` Promise resolves to the next free port.
  61. return choosePort(HOST, DEFAULT_PORT);
  62. })
  63. .then(port => {
  64. if (port == null) {
  65. // We have not found a port.
  66. return;
  67. }
  68. const protocol = process.env.HTTPS === 'true' ? 'https' : 'http';
  69. const appName = require(paths.appPackageJson).name;
  70. const urls = prepareUrls(protocol, HOST, port);
  71. // Create a webpack compiler that is configured with custom messages.
  72. const compiler = createCompiler(webpack, config, appName, urls, useYarn);
  73. // Load proxy config
  74. const proxySetting = require(paths.appPackageJson).proxy;
  75. const proxyConfig = prepareProxy(proxySetting, paths.appPublic);
  76. // Serve webpack assets generated by the compiler over a web server.
  77. const serverConfig = createDevServerConfig(
  78. proxyConfig,
  79. urls.lanUrlForConfig
  80. );
  81. const devServer = new WebpackDevServer(compiler, serverConfig);
  82. // Launch WebpackDevServer.
  83. devServer.listen(port, HOST, err => {
  84. if (err) {
  85. return console.log(err);
  86. }
  87. if (isInteractive) {
  88. clearConsole();
  89. }
  90. console.log(chalk.cyan('Starting the development server...\n'));
  91. openBrowser(urls.localUrlForBrowser);
  92. });
  93. ['SIGINT', 'SIGTERM'].forEach(function(sig) {
  94. process.on(sig, function() {
  95. devServer.close();
  96. process.exit();
  97. });
  98. });
  99. })
  100. .catch(err => {
  101. if (err && err.message) {
  102. console.log(err.message);
  103. }
  104. process.exit(1);
  105. });