Electron main process example for tray icon which minimizes / maximizes the app when clicked.

electron-main.js

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

// We create a null variables so that the tray and mainWindow
// don’t get removed by garbage collection
let tray = null;
let mainWindow = null;

app.on('window-all-closed', () => {
  if (process.platform != 'darwin') {
    app.quit();
  }
});

app.on('ready', () => {
  // http://stackoverflow.com/a/36232831/2110294
  tray = new Tray(`${__dirname}/icon-32x32.png`);
  // When the tray icon is clicked
  tray.on('click', () => {
    // http://stackoverflow.com/q/38193739/2110294
    if (mainWindow.isVisible()) {
      mainWindow.hide()
    } else {
      mainWindow.show()
    }
  });
  // Add the tool tip
  tray.setToolTip('Sample Application');

  mainWindow = new BrowserWindow({
    width: 800,
    height: 600
  });
  mainWindow.loadURL(`file://${__dirname}/index.html`);
  mainWindow.on('closed', () => {
    tray = null,
    mainWindow = null;
  });
});