index.js

const { app, Menu, BrowserWindow } = require("electron");
const path = require("path");

// 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 win;

function createWindow() {
  // Create the browser window.
  win = new BrowserWindow({
    width: 1100,
    height: 800
  });

  // and load the index.html of the app.
  win.loadFile("index.html");

  const options = { extraHeaders: "pragma: no-cache\n" };
  win.webContents.loadURL("https://messages.android.com/", options);

  // Open the DevTools.
  // win.webContents.openDevTools()

  // Emitted when the window is closed.
  win.on("closed", () => {
    // 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.
    win = null;
  });
}

function createMenu() {
  const application = {
    label: 'Application',
    submenu: [
      {
        label: 'About Application',
        role: 'about',
      },
      {
        type: 'separator',
      },
      {
        label: 'Quit',
        accelerator: 'Command+Q',
        click: () => {
          app.quit();
        },
      },
    ],
  };

  const edit = {
    label: "Edit",
    submenu: [
      {
        label: "Undo",
        accelerator: "CmdOrCtrl+Z",
        selector: "undo:"
      },
      {
        label: "Redo",
        accelerator: "Shift+CmdOrCtrl+Z",
        selector: "redo:"
      },
      {
        type: "separator"
      },
      {
        label: "Cut",
        accelerator: "CmdOrCtrl+X",
        selector: "cut:"
      },
      {
        label: "Copy",
        accelerator: "CmdOrCtrl+C",
        selector: "copy:"
      },
      {
        label: "Paste",
        accelerator: "CmdOrCtrl+V",
        selector: "paste:"
      },
      {
        label: "Select All",
        accelerator: "CmdOrCtrl+A",
        selector: "selectAll:"
      }
    ]
  }

  const template = [
    application,
    edit
  ]

  Menu.setApplicationMenu(Menu.buildFromTemplate(template))
}


// 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();
  createMenu();
});

// Quit when all windows are closed.
app.on("window-all-closed", () => {
  // On macOS 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", () => {
  // On macOS 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 (win === 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.