feat: Enhance FieldKeys and FieldType to support nested fields in Schema.

[christophe-g]

This should close #18.

[fwal]

Great! I'm looking into something similar for updates using Paths and Get from type-fest .

Could you also rebase-away me as co-author of d369085 😅

[christophe-g]

@fwal - thanks.

You can close this PR if you plan to include type-fest - I won't be offended ; ).

For the time being, I have a couple of @ts-expect-error for queries with nested keys and I am ok with this for a couple of additional days / weeks.

Out of curiosity - plans for Effect 4 for this lib? Not asking for an ETA, just to know if it will be there at some stage. Cheers !

[fwal]

Out of curiosity - plans for Effect 4 for this lib? Not asking for an ETA, just to know if it will be there at some stage. Cheers !

Not had time to dip my toes in just yet but will start work soon, thinking that an eventual 1.0 will run on Effect 4 🎉

[fwal]

Close/Reopen to trigger CI - long time, but let's get this merged 😅

[greptile-apps]

Greptile Summary

This PR extends Firestore query field-key and value-type utilities to support nested fields represented with dot notation.

• Recursively derives nested field paths through FieldKeys.
• Recursively resolves nested query value types through FieldType.

Confidence Score: 4/5

The nested field-value mapping should be corrected before merging because it accepts values belonging to sibling fields.

The new dotted-path branch ignores the inferred tail and feeds every nested key back into FieldType, weakening the type safety that the query APIs rely on.

Files Needing Attention: packages/effect-firebase/src/lib/firestore/query/query.ts

Important Files Changed

Filename	Overview
packages/effect-firebase/src/lib/firestore/query/query.ts	Adds nested field-path typing, but nested value resolution discards the requested suffix and returns a union of sibling field types.

_{Reviews (1): Last reviewed commit: "chore: revert indent spacing" | Re-trigger Greptile}

[greptile-apps]

Nested path tail is discarded

When querying a nested field whose siblings have different types, this branch passes every key below Head instead of the inferred Tail, so FieldType<S, "author.name"> becomes a sibling-type union and accepts invalid query values such as a number for a string field.

Suggested change

	? FieldType<S[Head], FieldKeys<S[Head]>>
	? FieldType<S[Head], Extract<Tail, FieldKeys<S[Head]>>>

[fwal]

Seems to cause a circular dependency in the examples

[christophe-g]

Seems to cause a circular dependency in the examples

Hmm, I indeed have some exception (ExcludedTypesT) in my production code, was hoping it would not be necessary here:

type effectLiteralArray = readonly (string)[]
type DotPrefix<T extends string> = T extends "" ? "" : `.${T}`
type DocumentReference = {
  firestore: any
  path: string
  id: string
  parent: any
}
type OptionT = Option.Option<any>
type ExcludedTypesT = Date | ((...args: any[]) => any) | Array<any> | effectLiteralArray |
  DocumentReference | Stripe.Invoice | File | FileSchemaT | FirestoreSchema.Reference | OptionT
// typeof Schema.Type 
export type NestedKeys<T> = (
  T extends ExcludedTypesT ? "" :
  // branded primitives (e.g. Effect Schema.brand) extend their primitive
  T extends (string | number | bigint | boolean | symbol) ? "" :
  T extends object ?
  { [K in Exclude<keyof T, symbol>]: `${K}${DotPrefix<NestedKeys<T[K]>>}` }[Exclude<keyof T, symbol>]
  : "") extends infer D ? Extract<D, string> : never

export type NestedValue<T, Key extends string> = Key extends `${infer K}.${infer Rest}` ?
  K extends keyof T ? NestedValue<T[K], Rest> : never :
  Key extends keyof T ? T[Key] : never

[fwal]

Landing nested fields for updates in #83 if that's of any help 😅

[fwal]

I took a stab on it in #84, hope you don't mind.

[christophe-g]

Of course not !

…

On Thu, Sep 10, 2026 at 1:32 PM Frederik Wallner ***@***.***> wrote: *fwal* left a comment (fwal/effect-firebase#25) <#25 (comment)> I took a stab on it in #84 <#84>, hope you don't mind. — Reply to this email directly, view it on GitHub <#25?email_source=notifications&email_token=AAI5FNO76YTD5LXJCSCPINT5OKGOTA5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTKNRRG44TQNRVGUY2M4TFMFZW63VGMF2XI2DPOKSWK5TFNZ2KYZTPN52GK4S7MNWGSY3L#issuecomment-5617986551>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAI5FNI2ZWEVJNTWBDQIHXL5OKGOTAVCNFSNUABGKJSXA33TNF2G64TZHMYTANZSGQ3DGNZYGI5US43TOVSTWNBQGE2TIMRZGIZTNILWAI> . Triage notifications, keep track of coding agent tasks and review pull requests on the go with GitHub Mobile for iOS <https://github.com/notifications/mobile/ios/AAI5FNKF2NUB5YGPDJIMZY35OKGOTA5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTKNRRG44TQNRVGUY2M4TFMFZW63VGMF2XI2DPOKSWK5TFNZ2KUZTPN52GK4S7NFXXG> and Android <https://github.com/notifications/mobile/android/AAI5FNIUEQHCWW42XDYKZXT5OKGOTA5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTKNRRG44TQNRVGUY2M4TFMFZW63VGMF2XI2DPOKSWK5TFNZ2K4ZTPN52GK4S7MFXGI4TPNFSA>. Download it today! You are receiving this because you authored the thread.Message ID: ***@***.***>

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