How to make an electron app using Create-React-App and Electron with Electron-Builder.

notes.md

Paraphrased from an excellent blog post by Christian Sepulveda

create-react-app my-app
cd my-app
yarn add electron --dev
yarn add foreman --dev # for process management
yarn install

Add electron-quick-start's main.js to src folder as electron-start.js.

Make it look like this:

const electron = require('electron');
// Module to control application life.
const app = electron.app;
// Module to create native browser window.
const BrowserWindow = electron.BrowserWindow;

const path = require('path');
const url = require('url');

// Keep a global reference of the window object, if you don't, the window will
// be closed automatically when the JavaScript object is garbage collected.
let mainWindow;

function createWindow() {
    // Create the browser window.
    mainWindow = new BrowserWindow({width: 800, height: 600});

    // and load the index.html of the app.
    const startUrl = process.env.ELECTRON_START_URL || url.format({
            pathname: path.join(__dirname, '/../build/index.html'),
            protocol: 'file:',
            slashes: true
        });
    mainWindow.loadURL(startUrl);
    // Open the DevTools.
    mainWindow.webContents.openDevTools();

    // Emitted when the window is closed.
    mainWindow.on('closed', function () {
        // Dereference the window object, usually you would store windows
        // in an array if your app supports multi windows, this is the time
        // when you should delete the corresponding element.
        mainWindow = null
    })
}

// This method will be called when Electron has finished
// initialization and is ready to create browser windows.
// Some APIs can only be used after this event occurs.
app.on('ready', createWindow);

// Quit when all windows are closed.
app.on('window-all-closed', function () {
    // On OS X it is common for applications and their menu bar
    // to stay active until the user quits explicitly with Cmd + Q
    if (process.platform !== 'darwin') {
        app.quit()
    }
});

app.on('activate', function () {
    // On OS X it's common to re-create a window in the app when the
    // dock icon is clicked and there are no other windows open.
    if (mainWindow === null) {
        createWindow()
    }
});

// In this file you can include the rest of your app's specific main process
// code. You can also put them in separate files and require them here.

Create a file called electron-wait-react.js in src directory:

const net = require('net');
const port = process.env.PORT ? (process.env.PORT - 100) : 3000;

process.env.ELECTRON_START_URL = `http://localhost:${port}`;

const client = new net.Socket();

let startedElectron = false;
const tryConnection = () => client.connect({port: port}, () => {
        client.end();
        if(!startedElectron) {
            console.log('starting electron');
            startedElectron = true;
            const exec = require('child_process').exec;
            exec('npm run electron');
        }
    }
);

tryConnection();

client.on('error', (error) => {
    setTimeout(tryConnection, 1000);
});

Make package.json look like this at the bottom:

"homepage": "./",
  "main": "src/electron-starter.js",
  "scripts": {
    "start": "nf start -p 3000",
    "build": "react-scripts build",
    "test": "react-scripts test --env=jsdom",
    "eject": "react-scripts eject",
    "electron": "electron .",
    "electron-start": "node src/electron-wait-react",
    "react-start": "react-scripts start"
  }

Add Procfile to root

react: npm run react-start
electron: npm run electron-start

Run using

yarn start