app.js

const path = require('path');
const url = require('url');
const trayIcon = require('./systemTray');

const electron = require('electron');
const app = electron.app;
const BrowserWindow = electron.BrowserWindow;

let win = null;

function createWindow() {
  win = new BrowserWindow({
    width: 302,
    height: 390,
    minWidth: 302,
    minHeight: 390,
    frame: false,
    resizable: false,
    maximizable: false,
    title: "Battery Watcher",
    icon: path.join(__dirname, '/src/images/battery-icon.png'),
    show: false
  });

  win.loadURL(url.format({
    pathname: path.join(__dirname, 'src/app.html'),
    protocol: 'file:',
    slashes: true
  }));
  trayIcon.showTrayMenu();
  win.once('ready-to-show', () => {
    win.show();
  });
}

// Create window on electron intialization
app.on('ready', createWindow);

// Quit when all windows are closed.
app.on('window-all-closed', function () {
  // On macOS specific close process
  if (process.platform !== 'darwin') {
    app.quit();
  }
});

app.on('activate', function () {
  // macOS specific close process
  if (win === null) {
    createWindow();
  }
});