Private Config variables are available on client side

[mnfgul]

Hi,
In my project I created all files same as the example project. However, I am getting "Error: Invalid next-firebase-auth options: The "firebaseAdminInitConfig" private key setting should not be available on the client side. The "cookies.keys" setting should not be available on the client side."

I suppose webpack is adding initConfig to client bundle. Is there a way to prevent this?