node.js – Role based authentication using Firebase and ReactJS

This is a advice seeking type post

I want to have two user types:

User
Admin
I’m going to user Firebase for authentication part only. Now let’s see what my users can do:

Register/login
Create post and make it public/private
Make a collection of post and make it public/private
And here’s what my admin can do:

Login
CRUD operation on users
View public/private posts and delete them
View public/private collection of posts and delete them
My question is can I do all of this using just Firebase and ReactJS? Or do I need a custom backend?

And what my rules for authenticaion for admin and user should look like if I just want a RBAC?

Is this enough?(found it in an article):

{
  "rules": {
    "users": {
      "$user": {
        ".write": "auth !== null && ((auth.token.isAdmin === true && data.child('isAdmin').val() === false) || auth.uid === $user)",
        ".read": "auth !== null && ((auth.token.isAdmin === true && data.child('isAdmin').val() === false) || auth.uid === $user)"
      },
      ".write": "auth !== null && auth.token.isAdmin === true",
      ".read": "auth !== null && auth.token.isAdmin === true"
    }
  }
}