electron exit to tray

index.js

const {
  app,
  BrowserWindow,
  Menu,
  Tray,
  nativeImage,
  ipcMain
} = require("electron");

let win, tray;
const createWindow = () => {
  win = new BrowserWindow({ width: 200, height: 200, show: false });
  win.once("ready-to-show", () => win.show());
  win.on("closed", () => (win = null));
  tray = new Tray(nativeImage.createEmpty());
  tray.setToolTip("el-pg");
  const contextMenu = Menu.buildFromTemplate([
    {
      label: "Show",
      type: "normal",
      click() {
        win.show();
      }
    },
    { label: "Exit", type: "normal", role: "quit" }
  ]);
  tray.on("click", () => (win.isVisible() ? win.hide() : win.show()));
  tray.setContextMenu(contextMenu);
  win.on("close", e => {
    if (win.isVisible()) {
      win.hide();
      e.preventDefault();
    }
  });
  win.loadFile("index.html");
};

app.on("ready", createWindow);

app.on("activate", () => {
  if (win == null) createWindow();
});

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

/*
  <script>
    const { ipcRenderer } = require('electron');
    function send(arg) {
      ipcRenderer.send('asynchronous-message', arg);
    }
  </script>
  <button onclick="send('tray')">win.hide();</button>
  <button onclick="send('quit')">app.quit();</button>
*/
ipcMain.on("asynchronous-message", (event, arg) => {
  if (arg === "tray") win.hide();
  if (arg === "quit") app.quit();
});