window.Twitch.ext.onAuthorized(
function(auth){
var parts=auth.token.split(".");
var payload=JSON.parse(window.atob(parts[1]));
var streamer_id = payload.channel_id;
}
);
Also:
var streamer_id = payload.opaque_user_id.replace('U', '');
A broadcaster’s token is set with “U” + his Twitch user ID, to avoid confusing his opaque ID with his user ID when he is a viewer.
Can also cross check that
payload.role == 'broadcaster'
To see if the ID’s below to the streamer that the extension is installed on