feat(firestore): Add data converter

[supersimple33]

Description

I have added the withConverter method which is provided in the JS sdk to the package here.

Release Summary

• Added withConverter to CollectionReference
• Created new interface FirestoreDataConverter

Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
  • Yes 🔥
• My change supports the following platforms;
  • Android
  • iOS
  • Other (macOS, web)
• My change includes tests;
  • e2e tests added or updated in packages/\*\*/e2e
  • jest tests added or updated in packages/\*\*/__tests__
• I have updated TypeScript types that are affected by my change.
• This is a breaking change;
  • Yes
  • No

Test Plan

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Project	Deployment	Preview	Comments	Updated (UTC)
react-native-firebase	Ready	Preview	Comment	Aug 23, 2025 5:55pm

[CLAassistant]

All committers have signed the CLA.

[supersimple33]

Bump!

[supersimple33]

Bump!

[macksal]

Have you noticed that CollectionReference only has one type param, but it's passed two?

export interface CollectionReference<T extends DocumentData = DocumentData> extends Query<T> {

In your method declaration:

withConverter<NewAppModelType, NewDbModelType extends DocumentData = DocumentData>(
  converter: FirestoreDataConverter<NewAppModelType>,
): CollectionReference<NewAppModelType, NewDbModelType>;

It's not just your code, I came across this PR because there's something wrong with these typings already.

[supersimple33]

Hey @macksal good catch I didn't notice it but you're right the types in this repo aren't yet inline with the firebase sdk since they are lacking the DbModel type im gonna remove that for now since adding it should be its own PR.

Edit: or actually after taking a quick look it may make more sense for me to just add it in now I guess since that type is needed elsewhere.