Too Long; Didn't Read
At Leave Me Alone we use Google and Microsoft OAuth for user sign in. Instead of redirecting it would be better if we could open a new window or popup for the OAuth flow. We use Passport for our authentication so when the user is directed back to our app after signing in the URL contains some parameters we need, including a token we use to authenticate them on our server. The process is quite simple and all we have done is add an intermediary step to pass through the callback parameters.