Access browser cookies

I’ve integrated RC using iFrame, authenticated user with token and set a cookie after the user is authenticated (in loginWithToken() of app/ui-utils/client/lib/IframeLogin.js). The goal is to access this cookie for fetching rooms, subscriptions etc.
The reason to use browser cookie is to identify a user’s specific category. I do not want to store this info in database as then I’ll have to query the db every time I want to use that value.
Any other work around is appreciated.