I’m writing to Firestore and creating a doc that has a field that is an Array of quite simple maps e.g.

docField : [
 {
   name: 'Bob',
   age: 42,
   type: 'default'
 }, ...
]

I want to write a security rule to validate the map fields and their request contents. I know I can validate fields with something like,

allow write:
   if request.resource.data.name is string
   && ...

But how do I apply this to all N of the items of an Array field?
I have seen some people just brute force each item in the list when the length is known but I don’t know how many items I’ll have to deal with – not hundreds but likely tens.

I can only think of putting each map into its own document in a subcollection and writing a rule for that but that seems like a lot of writes to perform for data that doesn’t require it.

Any tips?