fix: remove NO_ID_FIELD sentinel from data hooks when idField is not provided

[tyler-reitz]

Summary

• useFirestoreDocData, useFirestoreDocDataOnce, useFirestoreCollectionData, useDatabaseObjectData, and useDatabaseListData were passing the string 'NO_ID_FIELD' to rxfire's keyField option when no idField was provided by the caller
• This caused rxfire to add a property literally named "NO_ID_FIELD" (with the document ID as its value) to every returned document, polluting user data with an internal sentinel
• Fix passes undefined instead, which rxfire already handles correctly by omitting the ID field entirely
• Cache keys updated to use 'none' as the no-idField sentinel (replacing undefined, which stringifies to "undefined" in template literals and would make cache keys ambiguous)

Semver note

This is a bug fix: NO_ID_FIELD appearing in returned data was never documented or intentional behavior. Code reading result.NO_ID_FIELD would break, but that code was relying on a bug. Semver call (patch vs. minor/major) left to Jeff, and this may ship alongside #735.

Test plan

• TypeScript: clean
• Firestore emulator tests: 11/11 passing
• Covered by existing emulator test suite for useFirestoreCollectionData, useFirestoreDocData, and database equivalents

Fixes #295

[gemini-code-assist]

Code Review

This pull request updates the idField initialization logic in src/database.tsx and src/firestore.tsx to use undefined instead of a string literal, and updates the observableId generation to use the nullish coalescing operator for better readability. The reviewer suggests further simplifying the idField assignment by removing redundant ternary operators, as the checkIdField function already handles undefined inputs appropriately.

Important

The consumer version of Gemini Code Assist on GitHub is being sunset. Starting June 18, 2026, new organization installations will be blocked, and all code review activity will officially cease on July 17, 2026.
For more details on the timeline and next steps, please review the Help Documentation.

[gemini-code-assist]

This ternary expression is redundant. The checkIdField function already handles cases where options is undefined by returning undefined. You can simplify this to a direct call to checkIdField(options).

Suggested change

	const idField = options ? checkIdField(options) : undefined;
	const idField = checkIdField(options);

[tyler-reitz]

Declining: the ternary guard at the call site is intentional. checkIdField and checkOptions are typed to expect a real ReactFireOptions object, and the hooks handle the no-options case before calling them. Widening the signatures to accept undefined would require options: ReactFireOptions | undefined since field follows as a required parameter, which isn't a meaningful improvement. The current shape keeps the function signatures strict.

[gemini-code-assist]

This ternary expression is redundant. The checkIdField function already handles cases where options is undefined by returning undefined. You can simplify this to a direct call to checkIdField(options).

Suggested change

	const idField = options ? checkIdField(options) : undefined;
	const idField = checkIdField(options);

[tyler-reitz]

Declining: the ternary guard at the call site is intentional. checkIdField and checkOptions are typed to expect a real ReactFireOptions object, and the hooks handle the no-options case before calling them. Widening the signatures to accept undefined would require options: ReactFireOptions | undefined since field follows as a required parameter, which isn't a meaningful improvement. The current shape keeps the function signatures strict.

[gemini-code-assist]

This ternary expression is redundant. The checkIdField function already handles cases where options is undefined by returning undefined. You can simplify this to a direct call to checkIdField(options).

Suggested change

	const idField = options ? checkIdField(options) : undefined;
	const idField = checkIdField(options);

[tyler-reitz]

Declining: the ternary guard at the call site is intentional. checkIdField and checkOptions are typed to expect a real ReactFireOptions object, and the hooks handle the no-options case before calling them. Widening the signatures to accept undefined would require options: ReactFireOptions | undefined since field follows as a required parameter, which isn't a meaningful improvement. The current shape keeps the function signatures strict.

[gemini-code-assist]

This ternary expression is redundant. The checkIdField function already handles cases where options is undefined by returning undefined. You can simplify this to a direct call to checkIdField(options).

Suggested change

	const idField = options ? checkIdField(options) : undefined;
	const idField = checkIdField(options);

[tyler-reitz]

Declining: the ternary guard at the call site is intentional. checkIdField and checkOptions are typed to expect a real ReactFireOptions object, and the hooks handle the no-options case before calling them. Widening the signatures to accept undefined would require options: ReactFireOptions | undefined since field follows as a required parameter, which isn't a meaningful improvement. The current shape keeps the function signatures strict.

[gemini-code-assist]

This ternary expression is redundant. The checkIdField function already handles cases where options is undefined by returning undefined. You can simplify this to a direct call to checkIdField(options).

Suggested change

	const idField = options ? checkIdField(options) : undefined;
	const idField = checkIdField(options);

[tyler-reitz]

Declining: the ternary guard at the call site is intentional. checkIdField and checkOptions are typed to expect a real ReactFireOptions object, and the hooks handle the no-options case before calling them. Widening the signatures to accept undefined would require options: ReactFireOptions | undefined since field follows as a required parameter, which isn't a meaningful improvement. The current shape keeps the function signatures strict.