Operating System

All operating systems (Linux, macOS, Windows)

Environment (if applicable)

Node.js 20.12.2 (as specified in repository) Affects both browser and Node.js environments

Firebase SDK Version

Latest (main branch / v12.7.0)

Firebase SDK Product(s)

Firestore

Project Tooling

TypeScript, Yarn v1.22.22

Detailed Problem Description

The error messages in packages/firestore/src/lite-api/reference.ts use the outdated v8 naming convention "FirebaseFirestore" instead of the v9 modular API name "Firestore".

Location

• Line 516-517 in collection() function
• Line 654-655 in doc() function

What I was trying to achieve

While reviewing the codebase, I noticed inconsistency between the type names used in error messages and the actual type names in the v9 modular API.

What actually happened

The error messages still reference the old v8 name "FirebaseFirestore":

Expected first argument to collection() to be a CollectionReference, a DocumentReference or FirebaseFirestore

Expected behavior

The error messages should use the correct v9 type name "Firestore":

Expected first argument to collection() to be a CollectionReference, a DocumentReference or Firestore

Evidence of inconsistency

1. The type is imported as Firestore (line 40): import { Firestore } from './database';
2. All function signatures use firestore: Firestore
3. JSDoc comments consistently refer to it as Firestore
4. The class definition is export class Firestore (packages/firestore/src/lite-api/database.ts:68)

Impact

• Confuses developers using the v9 modular API
• Creates inconsistency between error messages and actual type names
• Makes error messages less helpful for debugging

Steps and code to reproduce issue

This is a static code issue (incorrect naming in error messages), but here's how to observe it:

Steps to verify the issue:

1. Clone the repository:

git clone https://github.com/firebase/firebase-js-sdk.git
cd firebase-js-sdk

2. Check the error messages:

grep -n "FirebaseFirestore" packages/firestore/src/lite-api/reference.ts

Output:

516:        'Expected first argument to collection() to be a CollectionReference, ' +
517:          'a DocumentReference or FirebaseFirestore'
654:        'Expected first argument to doc() to be a CollectionReference, ' +
655:          'a DocumentReference or Firestore'

3. Compare with actual type name:

grep -n "import { Firestore }" packages/firestore/src/lite-api/reference.ts

Output:

40:import { Firestore } from './database';

Code that would trigger this error (for context):

import { collection } from 'firebase/firestore';

// Passing undefined or invalid first argument
collection(undefined, 'users'); 
// Error: Expected first argument to collection() to be a CollectionReference, 
// a DocumentReference or FirebaseFirestore
//                        ^^^^^^^^^^^^^^^^^ <- Should say "Firestore"

Proposed fix

Replace "FirebaseFirestore" with "Firestore" in both locations (lines 517 and 655).

I'd be happy to submit a PR to fix this if the maintainers agree this should be changed.