main.js

// Modules to control application life and create native browser window
const { app, BrowserWindow, shell } = require('electron');

// 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,
        webPreferences: {
            // say explicitly to disable insecure content, more
            // https://github.com/electron/electron/blob/master/docs/tutorial/security.md#8-do-not-set-allowrunninginsecurecontent-to-true
            allowRunningInsecureContent: false,
            webSecurity: true,
            experimentalFeatures: false,
            nodeIntegration: false
            // TODO! more -> https://github.com/electron/electron/blob/master/docs/tutorial/security.md#2-disable-nodejs-integration-for-remote-content
            // preload: path.join(__dirname, 'preload.js')
        }
    });

    // and load the index.html of the app.
    mainWindow.loadURL(
        `file://${__dirname}/build/electron/index-electron.html`
    );
    // remove possiblity of eval from main window
    mainWindow.eval = global.eval = () => {
        throw new Error(`Sorry, this app does not support window.eval().`);
    };

    mainWindow.webContents.openDevTools();
    // 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();
    }
});

// TODO check if its good idea!
app.on('web-contents-created', (event, contents) => {
    contents.on('new-window', (event, navigationUrl) => {
        // Ask the operating system
        // to open this event's url in the default browser.
        event.preventDefault();

        shell.openExternal(navigationUrl);
    });
});

// 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.