Get user_id from OAuth token?

This is implicity auth

To get the user ID extract the access token from the URL hash

and pass the Token to the get users API, and this will return the user for that token, here is that example

https://barrycarlyon.github.io/twitch_misc/authentication/implicit_auth/

This is the correct method, and literally the purpose of oAuth

You don’t have the user ID. So how do you pass an additional parameter with the user ID in?

Same problem you don’t have the user ID in order to put it in state.