From 3c7a6d8278d3744e52329cd3c72770fd426c7fd0 Mon Sep 17 00:00:00 2001
From: Tyler Dixon <tylerdixon@google.com>
Date: Fri, 17 Jul 2026 13:07:06 -0700
Subject: [PATCH 1/2] fix: tighten ReactFireOptions generic types, remove T |
 any widening

Removes the `| any` escape hatch from `initialData` and `startWithValue`
in ReactFireOptions<T>, so passing a mismatched type is now a compile
error instead of silently accepted.

Also tightens the return types of `checkIdField` and `checkinitialData`,
and adds a cast in `useObservable` to handle the internal mismatch
between the hook's T and the raw Firebase observable type.

Closes #383
---
 src/firestore.tsx    |  6 +++---
 src/index.ts         | 12 ++++++------
 src/useObservable.ts |  2 +-
 3 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/src/firestore.tsx b/src/firestore.tsx
index 136d34e0..fa566cfd 100644
--- a/src/firestore.tsx
+++ b/src/firestore.tsx
@@ -63,7 +63,7 @@ export function useFirestoreDocData<T = unknown>(ref: DocumentReference<T>, opti
   const idField = options ? checkIdField(options) : 'NO_ID_FIELD';
 
   const observableId = `firestore:docData:${ref.firestore.app.name}:${ref.path}:idField=${idField}`;
-  const observable = docData(ref, { idField });
+  const observable = docData(ref, { idField: idField as keyof T });
 
   return useObservable(observableId, observable, options) as ObservableStatus<T>;
 }
@@ -75,7 +75,7 @@ export function useFirestoreDocDataOnce<T = unknown>(ref: DocumentReference<T>,
   const idField = options ? checkIdField(options) : 'NO_ID_FIELD';
 
   const observableId = `firestore:docDataOnce:${ref.firestore.app.name}:${ref.path}:idField=${idField}`;
-  const observable$ = docData(ref, { idField }).pipe(first());
+  const observable$ = docData(ref, { idField: idField as keyof T }).pipe(first());
 
   return useObservable(observableId, observable$, options) as ObservableStatus<T>;
 }
@@ -96,7 +96,7 @@ export function useFirestoreCollection<T = DocumentData>(query: FirestoreQuery<T
 export function useFirestoreCollectionData<T = DocumentData>(query: FirestoreQuery<T>, options?: ReactFireOptions<T[]>): ObservableStatus<T[]> {
   const idField = options ? checkIdField(options) : 'NO_ID_FIELD';
   const observableId = `firestore:collectionData:${getUniqueIdForFirestoreQuery(query)}:idField=${idField}`;
-  const observable$ = collectionData(query, { idField });
+  const observable$ = collectionData(query, { idField: idField as (string & keyof T) });
 
   return useObservable(observableId, observable$, options);
 }
diff --git a/src/index.ts b/src/index.ts
index ab60a1fe..df5ce614 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -23,11 +23,11 @@ export class ReactFireError extends Error {
 
 export interface ReactFireOptions<T = unknown> {
   idField?: string;
-  initialData?: T | any;
+  initialData?: T;
   /**
    * @deprecated use initialData instead
    */
-  startWithValue?: T | any;
+  startWithValue?: T;
   suspense?: boolean;
 }
 
@@ -40,12 +40,12 @@ export function checkOptions(options: ReactFireOptions, field: string) {
   throw new Error(`Field "${field}" is not a valid key in ReactFireOptions`);
 }
 
-export function checkinitialData(options: ReactFireOptions) {
-  return checkOptions(options, 'initialData');
+export function checkinitialData<T>(options: ReactFireOptions<T>): T | undefined {
+  return checkOptions(options, 'initialData') as T | undefined;
 }
 
-export function checkIdField(options: ReactFireOptions) {
-  return checkOptions(options, 'idField');
+export function checkIdField(options: ReactFireOptions): string | undefined {
+  return checkOptions(options, 'idField') as string | undefined;
 }
 
 export * from './auth';
diff --git a/src/useObservable.ts b/src/useObservable.ts
index 08e8c748..ed5bcfc4 100644
--- a/src/useObservable.ts
+++ b/src/useObservable.ts
@@ -127,7 +127,7 @@ export function useObservable<T = unknown>(observableId: string, source: Observa
 
   // modify the value if initialData exists
   if (!observable.hasValue && hasData) {
-    update.data = config?.initialData ?? config?.startWithValue;
+    update.data = (config?.initialData ?? config?.startWithValue) as T | undefined;
     update.status = 'success';
     update.hasEmitted = true;
   }

From b32f51a7e002980e097890e8868da444acf7687c Mon Sep 17 00:00:00 2001
From: Tyler Dixon <tylerdixon@google.com>
Date: Fri, 17 Jul 2026 13:27:48 -0700
Subject: [PATCH 2/2] refactor: simplify checkIdField, remove unused
 checkinitialData

checkIdField now reads options.idField directly (already string | undefined)
instead of routing through checkOptions and casting. checkinitialData had
no call sites and is removed.
---
 src/index.ts | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/src/index.ts b/src/index.ts
index df5ce614..c6bf3af0 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -40,12 +40,8 @@ export function checkOptions(options: ReactFireOptions, field: string) {
   throw new Error(`Field "${field}" is not a valid key in ReactFireOptions`);
 }
 
-export function checkinitialData<T>(options: ReactFireOptions<T>): T | undefined {
-  return checkOptions(options, 'initialData') as T | undefined;
-}
-
 export function checkIdField(options: ReactFireOptions): string | undefined {
-  return checkOptions(options, 'idField') as string | undefined;
+  return options?.idField;
 }
 
 export * from './auth';