Define key encoding/decoding strategy when using Codable with Firestore

[joshbruhin]

When using the FirebaseFirestoreSwift API to easily encode and decode Codable objects when saving and retrieving documents from Firestore, is it possible to set the .keyEncodingStrategy and .keyDecodingStrategy to be used by the Firestore encoder/decoder?

[mortenbekditlevsen]

That ought to be possible with the newly released v10 of the sdk.

[paulb777]

Thanks to @mortenbekditlevsen both for answering here and doing the implementation! 🎊

[andrewheard]

As simple example for anyone coming across this, if your keys were in snake_case you could read or write the following document:

let userRef = Firestore.firestore().collection("users").document()

Read

let decoder = Firestore.Decoder()
decoder.keyDecodingStrategy = .convertFromSnakeCase

let user: User? = try await userRef.getDocument(as: User.self, decoder: decoder)

Write

let encoder = Firestore.Encoder()
encoder.keyEncodingStrategy = .convertToSnakeCase

try userRef.setData(from: user, encoder: encoder)

Big thanks to @mortenbekditlevsen for this feature!

[KhaledShehadeh]

Just a quick note.
Do not use a same shared instance of decoder and encoder. This will result in a thread race.