How to Query a Type with an Array to Deref One Nested Type

If I have a document with a type called "page" and it has an array named "info" that contains 2 types: person (ref) and customField (document). How can I query page and ensure that person is deref but customField are not

You can use conditionals! https://www.sanity.io/docs/query-cheat-sheet#conditionals-64a36d80be73

The last example there should be what you need