Validation in MEAN stack .....?

I am developing a MEAN stack application but i stuck at validation(user-inputs). I know the client-side validations are done in Angular-JS but i am confused where to validate on server side. Either to use mongooose for validations or don't do any validation on mongooose(just store) do validations only in server(Node/express using some modules) or validate on both server-level and database-level....????

What should i do pls help me choose which practice is best.....????

Thanks.

via Himanshu Joshi