Connect Electron to Create React App

instructions.bash

create-react-app $NAME
npm install --save electron
npm run eject
replace scripts/start.js with this start.js
replace config/webpack.config.dev.js with this webpack.config.dev.js

start.js

'use strict';

process.env.NODE_ENV = 'development';

// Load environment variables from .env file. Suppress warnings using silent
// if this file is missing. dotenv will never modify any environment variables
// that have already been set.
// https://github.com/motdotla/dotenv
require('dotenv').config({silent: true});

var chalk = require('chalk');
var webpack = require('webpack');
var WebpackDevServer = require('webpack-dev-server');
var historyApiFallback = require('connect-history-api-fallback');
var httpProxyMiddleware = require('http-proxy-middleware');
var detect = require('detect-port');
var clearConsole = require('react-dev-utils/clearConsole');
var checkRequiredFiles = require('react-dev-utils/checkRequiredFiles');
var formatWebpackMessages = require('react-dev-utils/formatWebpackMessages');
var getProcessForPort = require('react-dev-utils/getProcessForPort');
var openBrowser = require('react-dev-utils/openBrowser');
var prompt = require('react-dev-utils/prompt');
var fs = require('fs');
var config = require('../config/webpack.config.dev');
var paths = require('../config/paths');

var spawn = require('child_process').spawn;
var electron = require('electron');

var useYarn = fs.existsSync(paths.yarnLockFile);
var cli = useYarn ? 'yarn' : 'npm';
var 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.
var DEFAULT_PORT = parseInt(process.env.PORT, 10) || 3000;
var compiler;
var handleCompile;

// You can safely remove this after ejecting.
// We only use this block for testing of Create React App itself:
var isSmokeTest = process.argv.some(arg => arg.indexOf('--smoke-test') > -1);
if (isSmokeTest) {
  handleCompile = function (err, stats) {
    if (err || stats.hasErrors() || stats.hasWarnings()) {
      process.exit(1);
    } else {
      process.exit(0);
    }
  };
}

var hasStartedElectron = false;

function setupCompiler(host, port, protocol) {
  // "Compiler" is a low-level interface to Webpack.
  // It lets us listen to some events and provide our own custom messages.
  compiler = webpack(config, handleCompile);

  // "invalid" event fires when you have changed a file, and Webpack is
  // recompiling a bundle. WebpackDevServer takes care to pause serving the
  // bundle, so if you refresh, it'll wait instead of serving the old one.
  // "invalid" is short for "bundle invalidated", it doesn't imply any errors.
  compiler.plugin('invalid', function() {
    if (isInteractive) {
      clearConsole();
    }
    console.log('Compiling...');
  });

  var isFirstCompile = true;

  // "done" event fires when Webpack has finished recompiling the bundle.
  // Whether or not you have warnings or errors, you will get this event.
  compiler.plugin('done', function(stats) {
    if (isInteractive) {
      clearConsole();
    }

    // We have switched off the default Webpack output in WebpackDevServer
    // options so we are going to "massage" the warnings and errors and present
    // them in a readable focused way.
    var messages = formatWebpackMessages(stats.toJson({}, true));
    var isSuccessful = !messages.errors.length && !messages.warnings.length;
    var showInstructions = isSuccessful && (isInteractive || isFirstCompile);

    if (isSuccessful) {
      console.log(chalk.green('Compiled successfully!'));
    }

    if (!hasStartedElectron) {
      spawn(electron, ['.']);
      hasStartedElectron = true;
    }

    if (showInstructions) {
      console.log();
      console.log('The app is running at:');
      console.log();
      console.log('  ' + chalk.cyan(protocol + '://' + host + ':' + port + '/'));
      console.log();
      console.log('Note that the development build is not optimized.');
      console.log('To create a production build, use ' + chalk.cyan(cli + ' run build') + '.');
      console.log();
      isFirstCompile = false;
    }

    // If errors exist, only show errors.
    if (messages.errors.length) {
      console.log(chalk.red('Failed to compile.'));
      console.log();
      messages.errors.forEach(message => {
        console.log(message);
        console.log();
      });
      return;
    }

    // Show warnings if no errors were found.
    if (messages.warnings.length) {
      console.log(chalk.yellow('Compiled with warnings.'));
      console.log();
      messages.warnings.forEach(message => {
        console.log(message);
        console.log();
      });
      // Teach some ESLint tricks.
      console.log('You may use special comments to disable some warnings.');
      console.log('Use ' + chalk.yellow('// eslint-disable-next-line') + ' to ignore the next line.');
      console.log('Use ' + chalk.yellow('/* eslint-disable */') + ' to ignore all warnings in a file.');
    }
  });
}

// We need to provide a custom onError function for httpProxyMiddleware.
// It allows us to log custom error messages on the console.
function onProxyError(proxy) {
  return function(err, req, res){
    var host = req.headers && req.headers.host;
    console.log(
      chalk.red('Proxy error:') + ' Could not proxy request ' + chalk.cyan(req.url) +
      ' from ' + chalk.cyan(host) + ' to ' + chalk.cyan(proxy) + '.'
    );
    console.log(
      'See https://nodejs.org/api/errors.html#errors_common_system_errors for more information (' +
      chalk.cyan(err.code) + ').'
    );
    console.log();

    // And immediately send the proper error response to the client.
    // Otherwise, the request will eventually timeout with ERR_EMPTY_RESPONSE on the client side.
    if (res.writeHead && !res.headersSent) {
        res.writeHead(500);
    }
    res.end('Proxy error: Could not proxy request ' + req.url + ' from ' +
      host + ' to ' + proxy + ' (' + err.code + ').'
    );
  }
}

function addMiddleware(devServer) {
  // `proxy` lets you to specify a fallback server during development.
  // Every unrecognized request will be forwarded to it.
  var proxy = require(paths.appPackageJson).proxy;
  devServer.use(historyApiFallback({
    // Paths with dots should still use the history fallback.
    // See https://github.com/facebookincubator/create-react-app/issues/387.
    disableDotRule: true,
    // For single page apps, we generally want to fallback to /index.html.
    // However we also want to respect `proxy` for API calls.
    // So if `proxy` is specified, we need to decide which fallback to use.
    // We use a heuristic: if request `accept`s text/html, we pick /index.html.
    // Modern browsers include text/html into `accept` header when navigating.
    // However API calls like `fetch()` won’t generally accept text/html.
    // If this heuristic doesn’t work well for you, don’t use `proxy`.
    htmlAcceptHeaders: proxy ?
      ['text/html'] :
      ['text/html', '*/*']
  }));
  if (proxy) {
    if (typeof proxy !== 'string') {
      console.log(chalk.red('When specified, "proxy" in package.json must be a string.'));
      console.log(chalk.red('Instead, the type of "proxy" was "' + typeof proxy + '".'));
      console.log(chalk.red('Either remove "proxy" from package.json, or make it a string.'));
      process.exit(1);
    }

    // Otherwise, if proxy is specified, we will let it handle any request.
    // There are a few exceptions which we won't send to the proxy:
    // - /index.html (served as HTML5 history API fallback)
    // - /*.hot-update.json (WebpackDevServer uses this too for hot reloading)
    // - /sockjs-node/* (WebpackDevServer uses this for hot reloading)
    // Tip: use https://jex.im/regulex/ to visualize the regex
    var mayProxy = /^(?!\/(index\.html$|.*\.hot-update\.json$|sockjs-node\/)).*$/;

    // Pass the scope regex both to Express and to the middleware for proxying
    // of both HTTP and WebSockets to work without false positives.
    var hpm = httpProxyMiddleware(pathname => mayProxy.test(pathname), {
      target: proxy,
      logLevel: 'silent',
      onProxyReq: function(proxyReq) {
        // Browers may send Origin headers even with same-origin
        // requests. To prevent CORS issues, we have to change
        // the Origin to match the target URL.
        if (proxyReq.getHeader('origin')) {
          proxyReq.setHeader('origin', proxy);
        }
      },
      onError: onProxyError(proxy),
      secure: false,
      changeOrigin: true,
      ws: true,
      xfwd: true
    });
    devServer.use(mayProxy, hpm);

    // Listen for the websocket 'upgrade' event and upgrade the connection.
    // If this is not done, httpProxyMiddleware will not try to upgrade until
    // an initial plain HTTP request is made.
    devServer.listeningApp.on('upgrade', hpm.upgrade);
  }

  // Finally, by now we have certainly resolved the URL.
  // It may be /index.html, so let the dev server try serving it again.
  devServer.use(devServer.middleware);
}

function runDevServer(host, port, protocol) {
  var devServer = new WebpackDevServer(compiler, {
    // Enable gzip compression of generated files.
    compress: true,
    // Silence WebpackDevServer's own logs since they're generally not useful.
    // It will still show compile warnings and errors with this setting.
    clientLogLevel: 'none',
    // By default WebpackDevServer serves physical files from current directory
    // in addition to all the virtual build products that it serves from memory.
    // This is confusing because those files won’t automatically be available in
    // production build folder unless we copy them. However, copying the whole
    // project directory is dangerous because we may expose sensitive files.
    // Instead, we establish a convention that only files in `public` directory
    // get served. Our build script will copy `public` into the `build` folder.
    // In `index.html`, you can get URL of `public` folder with %PUBLIC_URL%:
    // <link rel="shortcut icon" href="%PUBLIC_URL%/favicon.ico">
    // In JavaScript code, you can access it with `process.env.PUBLIC_URL`.
    // Note that we only recommend to use `public` folder as an escape hatch
    // for files like `favicon.ico`, `manifest.json`, and libraries that are
    // for some reason broken when imported through Webpack. If you just want to
    // use an image, put it in `src` and `import` it from JavaScript instead.
    contentBase: paths.appPublic,
    // Enable hot reloading server. It will provide /sockjs-node/ endpoint
    // for the WebpackDevServer client so it can learn when the files were
    // updated. The WebpackDevServer client is included as an entry point
    // in the Webpack development configuration. Note that only changes
    // to CSS are currently hot reloaded. JS changes will refresh the browser.
    hot: true,
    // It is important to tell WebpackDevServer to use the same "root" path
    // as we specified in the config. In development, we always serve from /.
    publicPath: config.output.publicPath,
    // WebpackDevServer is noisy by default so we emit custom message instead
    // by listening to the compiler events with `compiler.plugin` calls above.
    quiet: true,
    // Reportedly, this avoids CPU overload on some systems.
    // https://github.com/facebookincubator/create-react-app/issues/293
    watchOptions: {
      ignored: /node_modules/
    },
    // Enable HTTPS if the HTTPS environment variable is set to 'true'
    https: protocol === "https",
    host: host
  });

  // Our custom middleware proxies requests to /index.html or a remote API.
  addMiddleware(devServer);

  // Launch WebpackDevServer.
  devServer.listen(port, err => {
    if (err) {
      return console.log(err);
    }

    if (isInteractive) {
      clearConsole();
    }
    console.log(chalk.cyan('Starting the development server...'));
    console.log();

    openBrowser(protocol + '://' + host + ':' + port + '/');
  });
}

function run(port) {
  var protocol = process.env.HTTPS === 'true' ? "https" : "http";
  var host = process.env.HOST || 'localhost';
  setupCompiler(host, port, protocol);
  runDevServer(host, port, protocol);
}

// We attempt to use the default port but if it is busy, we offer the user to
// run on a different port. `detect()` Promise resolves to the next free port.
detect(DEFAULT_PORT).then(port => {
  if (port === DEFAULT_PORT) {
    run(port);
    return;
  }

  if (isInteractive) {
    clearConsole();
    var existingProcess = getProcessForPort(DEFAULT_PORT);
    var question =
      chalk.yellow('Something is already running on port ' + DEFAULT_PORT + '.' +
        ((existingProcess) ? ' Probably:\n  ' + existingProcess : '')) +
        '\n\nWould you like to run the app on another port instead?';

    prompt(question, true).then(shouldChangePort => {
      if (shouldChangePort) {
        run(port);
      }
    });
  } else {
    console.log(chalk.red('Something is already running on port ' + DEFAULT_PORT + '.'));
  }
});

webpack.config.dev.js

'use strict';

var autoprefixer = require('autoprefixer');
var webpack = require('webpack');
var HtmlWebpackPlugin = require('html-webpack-plugin');
var CaseSensitivePathsPlugin = require('case-sensitive-paths-webpack-plugin');
var InterpolateHtmlPlugin = require('react-dev-utils/InterpolateHtmlPlugin');
var WatchMissingNodeModulesPlugin = require('react-dev-utils/WatchMissingNodeModulesPlugin');
var getClientEnvironment = require('./env');
var paths = require('./paths');



// Webpack uses `publicPath` to determine where the app is being served from.
// In development, we always serve from the root. This makes config easier.
var publicPath = '/';
// `publicUrl` is just like `publicPath`, but we will provide it to our app
// as %PUBLIC_URL% in `index.html` and `process.env.PUBLIC_URL` in JavaScript.
// Omit trailing slash as %PUBLIC_PATH%/xyz looks better than %PUBLIC_PATH%xyz.
var publicUrl = '';
// Get environment variables to inject into our app.
var env = getClientEnvironment(publicUrl);

// This is the development configuration.
// It is focused on developer experience and fast rebuilds.
// The production configuration is different and lives in a separate file.
module.exports = {
  // You may want 'eval' instead if you prefer to see the compiled output in DevTools.
  // See the discussion in https://github.com/facebookincubator/create-react-app/issues/343.
  devtool: 'cheap-module-source-map',
  // These are the "entry points" to our application.
  // This means they will be the "root" imports that are included in JS bundle.
  // The first two entry points enable "hot" CSS and auto-refreshes for JS.
  entry: [
    // Include an alternative client for WebpackDevServer. A client's job is to
    // connect to WebpackDevServer by a socket and get notified about changes.
    // When you save a file, the client will either apply hot updates (in case
    // of CSS changes), or refresh the page (in case of JS changes). When you
    // make a syntax error, this client will display a syntax error overlay.
    // Note: instead of the default WebpackDevServer client, we use a custom one
    // to bring better experience for Create React App users. You can replace
    // the line below with these two lines if you prefer the stock client:
    // require.resolve('webpack-dev-server/client') + '?/',
    // require.resolve('webpack/hot/dev-server'),
    require.resolve('react-dev-utils/webpackHotDevClient'),
    // We ship a few polyfills by default:
    require.resolve('./polyfills'),
    // Finally, this is your app's code:
    paths.appIndexJs
    // We include the app code last so that if there is a runtime error during
    // initialization, it doesn't blow up the WebpackDevServer client, and
    // changing JS code would still trigger a refresh.
  ],
  output: {
    // Next line is not used in dev but WebpackDevServer crashes without it:
    path: paths.appBuild,
    // Add /* filename */ comments to generated require()s in the output.
    pathinfo: true,
    // This does not produce a real file. It's just the virtual path that is
    // served by WebpackDevServer in development. This is the JS bundle
    // containing code from all our entry points, and the Webpack runtime.
    filename: 'static/js/bundle.js',
    // This is the URL that app is served from. We use "/" in development.
    publicPath: publicPath
  },
  resolve: {
    // This allows you to set a fallback for where Webpack should look for modules.
    // We read `NODE_PATH` environment variable in `paths.js` and pass paths here.
    // We use `fallback` instead of `root` because we want `node_modules` to "win"
    // if there any conflicts. This matches Node resolution mechanism.
    // https://github.com/facebookincubator/create-react-app/issues/253
    fallback: paths.nodePaths,
    // These are the reasonable defaults supported by the Node ecosystem.
    // We also include JSX as a common component filename extension to support
    // some tools, although we do not recommend using it, see:
    // https://github.com/facebookincubator/create-react-app/issues/290
    extensions: ['.js', '.json', '.jsx', ''],
    alias: {
      // Support React Native Web
      // https://www.smashingmagazine.com/2016/08/a-glimpse-into-the-future-with-react-native-for-web/
      'react-native': 'react-native-web'
    }
  },
  
  module: {
    // First, run the linter.
    // It's important to do this before Babel processes the JS.
    preLoaders: [
      {
        test: /\.(js|jsx)$/,
        loader: 'eslint',
        include: paths.appSrc,
      }
    ],
    loaders: [
      // ** ADDING/UPDATING LOADERS **
      // The "url" loader handles all assets unless explicitly excluded.
      // The `exclude` list *must* be updated with every change to loader extensions.
      // When adding a new loader, you must add its `test`
      // as a new entry in the `exclude` list for "url" loader.

      // "url" loader embeds assets smaller than specified size as data URLs to avoid requests.
      // Otherwise, it acts like the "file" loader.
      {
        exclude: [
          /\.html$/,
          // We have to write /\.(js|jsx)(\?.*)?$/ rather than just /\.(js|jsx)$/
          // because you might change the hot reloading server from the custom one
          // to Webpack's built-in webpack-dev-server/client?/, which would not
          // get properly excluded by /\.(js|jsx)$/ because of the query string.
          // Webpack 2 fixes this, but for now we include this hack.
          // https://github.com/facebookincubator/create-react-app/issues/1713
          /\.(js|jsx)(\?.*)?$/,
          /\.css$/,
          /\.json$/,
          /\.svg$/
        ],
        loader: 'url',
        query: {
          limit: 10000,
          name: 'static/media/[name].[hash:8].[ext]'
        }
      },
      // Process JS with Babel.
      {
        test: /\.(js|jsx)$/,
        include: paths.appSrc,
        loader: 'babel',
        query: {
          
          // This is a feature of `babel-loader` for webpack (not Babel itself).
          // It enables caching results in ./node_modules/.cache/babel-loader/
          // directory for faster rebuilds.
          cacheDirectory: true
        }
      },
      // "postcss" loader applies autoprefixer to our CSS.
      // "css" loader resolves paths in CSS and adds assets as dependencies.
      // "style" loader turns CSS into JS modules that inject <style> tags.
      // In production, we use a plugin to extract that CSS to a file, but
      // in development "style" loader enables hot editing of CSS.
      {
        test: /\.css$/,
        loader: 'style!css?importLoaders=1!postcss'
      },
      // JSON is not enabled by default in Webpack but both Node and Browserify
      // allow it implicitly so we also enable it.
      {
        test: /\.json$/,
        loader: 'json'
      },
      // "file" loader for svg
      {
        test: /\.svg$/,
        loader: 'file',
        query: {
          name: 'static/media/[name].[hash:8].[ext]'
        }
      }
      // ** STOP ** Are you adding a new loader?
      // Remember to add the new extension(s) to the "url" loader exclusion list.
    ]
  },

  target: 'electron-renderer',
  
  // We use PostCSS for autoprefixing only.
  postcss: function() {
    return [
      autoprefixer({
        browsers: [
          '>1%',
          'last 4 versions',
          'Firefox ESR',
          'not ie < 9', // React doesn't support IE8 anyway
        ]
      }),
    ];
  },
  plugins: [
    // Makes some environment variables available in index.html.
    // The public URL is available as %PUBLIC_URL% in index.html, e.g.:
    // <link rel="shortcut icon" href="%PUBLIC_URL%/favicon.ico">
    // In development, this will be an empty string.
    new InterpolateHtmlPlugin(env.raw),
    // Generates an `index.html` file with the <script> injected.
    new HtmlWebpackPlugin({
      inject: true,
      template: paths.appHtml,
    }),
    // Makes some environment variables available to the JS code, for example:
    // if (process.env.NODE_ENV === 'development') { ... }. See `./env.js`.
    new webpack.DefinePlugin(env.stringified),
    // This is necessary to emit hot updates (currently CSS only):
    new webpack.HotModuleReplacementPlugin(),
    // Watcher doesn't work well if you mistype casing in a path so we use
    // a plugin that prints an error when you attempt to do this.
    // See https://github.com/facebookincubator/create-react-app/issues/240
    new CaseSensitivePathsPlugin(),
    // If you require a missing module and then `npm install` it, you still have
    // to restart the development server for Webpack to discover it. This plugin
    // makes the discovery automatic so you don't have to restart.
    // See https://github.com/facebookincubator/create-react-app/issues/186
    new WatchMissingNodeModulesPlugin(paths.appNodeModules)
  ]
};