Facebook, OAuth login. Correct opener in window

main.js

mainWindow = new BrowserWindow({
  webPreferences: {
    nativeWindowOpen: true,// window.open return Window object(like in regular browsers), not BrowserWindowProxy
    affinity: 'main-window'// main window, and addition windows should work in one process
  }
});

mainWindow.webContents.on('new-window', function (e, url, frameName, disposition, options) {
  // hook on new opened window

  // at now new window in mainWindow renderer process.
  // Also, this will automatically get an option `nodeIntegration=false`(not override to true, like in iframe's) - like in regular browsers
  options.webPreferences.affinity = 'main-window';
});

It will be great if you could add the new window implementation inside the 'new-window' event handler.

mainWindow.webContents.on('new-window', function (e, url, frameName, disposition, options) {
  options.webPreferences.affinity = 'main-window';
Object.assign(options, {
      width: 100,
      height: 100
    })
    e.newGuest = new BrowserWindow(options)
});

It seems like the above code is not working.

This worked(in your example, prevention is forgotten):

mainWindow.webContents.on('new-window', function (e, url, frameName, disposition, options) {
    options.webPreferences.affinity = 'main-window';
    Object.assign(options, {
      width: 100,
      height: 500
    })
    // not really need uncomment next lines. not sure, but navigation(in child window) may break, or something else
    // e.newGuest = new BrowserWindow(options)
    // e.preventDefault();
  });

I also want to note that the workaround works only in the electron@2
In my last tests, this solution not actually worked at electron@3-4