index.js

const { app, BrowserWindow } = require("electron");
let mainWindow;

// this should be placed at top of main.js to handle setup events quickly
if (handleSquirrelEvent(app)) {
  // squirrel event handled and app will exit in 1000ms, so don't do anything else
  return;
}

app.on("ready", () => {
  mainWindow = new BrowserWindow({
    height: 800,
    width: 800,
    icon: "./res/icon_192.png"
  });

  mainWindow.loadURL("file://" + __dirname + "/index.html");
});

app.on("browser-window-created", function(e, window) {
  window.setMenu(null);
});

function handleSquirrelEvent(application) {
  if (process.argv.length === 1) {
    return false;
  }

  const ChildProcess = require("child_process");
  const path = require("path");

  const appFolder = path.resolve(process.execPath, "..");
  const rootAtomFolder = path.resolve(appFolder, "..");
  const updateDotExe = path.resolve(path.join(rootAtomFolder, "Update.exe"));
  const exeName = path.basename(process.execPath);

  const spawn = function(command, args) {
    let spawnedProcess, error;

    try {
      spawnedProcess = ChildProcess.spawn(command, args, {
        detached: true
      });
    } catch (error) {}

    return spawnedProcess;
  };

  const spawnUpdate = function(args) {
    return spawn(updateDotExe, args);
  };

  const squirrelEvent = process.argv[1];
  switch (squirrelEvent) {
    case "--squirrel-install":
    case "--squirrel-updated":
      // Optionally do things such as:
      // - Add your .exe to the PATH
      // - Write to the registry for things like file associations and
      //   explorer context menus

      // Install desktop and start menu shortcuts
      spawnUpdate(["--createShortcut", exeName]);

      setTimeout(application.quit, 1000);
      return true;

    case "--squirrel-uninstall":
      // Undo anything you did in the --squirrel-install and
      // --squirrel-updated handlers

      // Remove desktop and start menu shortcuts
      spawnUpdate(["--removeShortcut", exeName]);

      setTimeout(application.quit, 1000);
      return true;

    case "--squirrel-obsolete":
      // This is called on the outgoing version of your app before
      // we update to the new version - it's the opposite of
      // --squirrel-updated

      application.quit();
      return true;
  }
}