Get all fields present on leads

Hey there,
I was trying to get all fields that are present on “leads”. For “deals” we have “dealFields” to get all fields present on “deals”.
How one can get all fields present on “leads”?
Also what is relation between between “leads” & “deals”, when compared schemas?

I couldn’t find an API to fetch lead fields as well. So hard coded at the moment based on the available fields