main.js

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

var mainWindow = null;

// These needed definitely be defined outside function scope: https://github.com/electron/electron/issues/822
var appIcon = null;
var contextMenu = null;

function createWindow() {
  // Create the browser window.
  const mainWindow = new BrowserWindow({
    width: 650,
    height: 250,
    webPreferences: {
      preload: path.join(__dirname, 'preload.js')
    },
    icon: path.join(__dirname, 'Icon-48.png'),
    title: "Service Desk Queue Change Alert"
  })

  // and load the index.html of the app.
  mainWindow.loadFile('index.html')

  mainWindow.on('minimize', function (event) {
    event.preventDefault();
    mainWindow.hide();
  });

  mainWindow.on('close', function (event) {
    if (!app.isQuitting) {
      event.preventDefault();
      mainWindow.hide();
    }

    return false;
  });

  // Hides menu for windows app
  // mainWindow.setMenu(null);

  appIcon = new Tray(path.join(__dirname, 'Icon-16.png'));
  contextMenu = Menu.buildFromTemplate([
    {
      label: 'Show App', click: function () {
        mainWindow.show();
      }
    },
    {
      label: 'Quit', click: function () {
        app.isQuitting = true;
        app.quit();
      }
    }
  ]);
  appIcon.setToolTip('Service Desk Queue Change Alert');
  appIcon.setContextMenu(contextMenu);

  // Open the DevTools.
  // mainWindow.webContents.openDevTools()
}

// 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.whenReady().then(createWindow)

// Quit when all windows are closed.
app.on('window-all-closed', function () {
  // 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', function () {
  // 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 (BrowserWindow.getAllWindows().length === 0) 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.