How to filter Firestore collection data using function (for location distance filtering)

Question

Would like to know how to filter a Firestore collection of docs using a function where some of the function args are the values of the collection documents.

Suppose had

Answer 1

So as answered previously, Firestore doesn't support native geo queries. This is a bit of a shameful plug for some open source stuff I've been working on...

https://github.com/mbramwell1/GeoFire-Android

That lets you do standard Firestore queries, but also adds in the ability to search by location aswell. Give it a look over it may do what you want.