main.js

const { app, dialog, BrowserWindow, ipcMain, Menu } = require('electron')
const path = require('path')
const { writeFileSync } = require('fs');
require('update-electron-app')()

// set empty Menu
//const menu = new Menu();
//Menu.setApplicationMenu(menu);

if (handleSquirrelEvent()) {
  // squirrel event handled and app will exit in 1000ms, so don't do anything else
  return;
}

function handleSquirrelEvent() {
  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(app.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(app.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

      app.quit();
      return true;
  }
};

const createWindow = () => {
  const mainWindow = new BrowserWindow({
    width: 800,
    height: 600,
    autoHideMenuBar: true,
    webPreferences: {
      preload: path.join(__dirname, 'preload.js'),
    },
  })

  mainWindow.webContents.session.on('select-serial-port', (event, portList, webContents, callback) => {

    //Add listeners to handle ports being added or removed before the callback for `select-serial-port`
    //is called.
    mainWindow.webContents.session.on('serial-port-added', (event, port) => {
      console.log('serial-port-added FIRED WITH', port)
      //Optionally update portList to add the new port
    })
  
    mainWindow.webContents.session.on('serial-port-removed', (event, port) => {
      console.log('serial-port-removed FIRED WITH', port)
      //Optionally update portList to remove the port
    })

    event.preventDefault()
    if (portList && portList.length > 0) {
      callback(portList[0].portId)
    } else {
      callback('') //Could not find any matching devices
    }
  })

  mainWindow.webContents.session.setPermissionCheckHandler((webContents, permission, requestingOrigin, details) => {
    if (permission === 'serial' && details.securityOrigin === 'file:///') {
      return true
    }
    
    return false
  })

  mainWindow.webContents.session.setDevicePermissionHandler((details) => {
    if (details.deviceType === 'serial' && details.origin === 'file://') {
      return true
    }
    
    return false
  })

  mainWindow.loadFile('index.html')
  
  //mainWindow.webContents.openDevTools()
}


const handleDataDump = (event, data) => {
  let path = dialog.showSaveDialogSync({ filters: [
    { name: 'CSV', extensions: ['csv'] },
    { name: 'All Files', extensions: ['*'] }
  ]});

  try {
    writeFileSync(path,data,{encoding:'utf8',flag:'w'})
  } catch (err) {
    console.error(err);
  }
}

app.whenReady().then(() => {
  createWindow()

  ipcMain.on('download', handleDataDump);
  ipcMain.handle('version', app.getVersion);

  app.on('activate', () => {
    if (BrowserWindow.getAllWindows().length === 0) createWindow()
  })
})

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