v2 Firestore Triggers Type definitions define .data property on FirestoreEvents as possibly undefined

[wneild]

Related issues

[REQUIRED] Version info

node: 16.20.0

firebase-functions: 4.4.1

firebase-tools: 12.3.0

firebase-admin: 11.10.1

[REQUIRED] Test case

export const exampleHandler = onDocumentCreated('example/{docId}', async (event) => {
	const docId = event.data?.id; // event data is possibly undefined
	info(docId);
});

[REQUIRED] Steps to reproduce

1. Write the above code in a Node with Typescript configured environment
2. Observe the need to handle possibly undefined event data

[REQUIRED] Expected behavior

I expect every Firestore event to, at minimum, have data on what occurred and never be undefined.

[REQUIRED] Actual behavior

I am required to handle the possibility of undefined data on all Firestore events as per the following type defs:

export declare function onDocumentWritten<Document extends string>(document: Document, handler: (event: FirestoreEvent<Change<DocumentSnapshot> | undefined, ParamsOf<Document>>) => any | Promise<any>): CloudFunction<FirestoreEvent<Change<DocumentSnapshot> | undefined, ParamsOf<Document>>>;

export declare function onDocumentWritten<Document extends string>(opts: DocumentOptions<Document>, handler: (event: FirestoreEvent<Change<DocumentSnapshot> | undefined, ParamsOf<Document>>) => any | Promise<any>): CloudFunction<FirestoreEvent<Change<DocumentSnapshot> | undefined, ParamsOf<Document>>>;

export declare function onDocumentCreated<Document extends string>(document: Document, handler: (event: FirestoreEvent<QueryDocumentSnapshot | undefined, ParamsOf<Document>>) => any | Promise<any>): CloudFunction<FirestoreEvent<QueryDocumentSnapshot | undefined, ParamsOf<Document>>>;

export declare function onDocumentCreated<Document extends string>(opts: DocumentOptions<Document>, handler: (event: FirestoreEvent<QueryDocumentSnapshot | undefined, ParamsOf<Document>>) => any | Promise<any>): CloudFunction<FirestoreEvent<QueryDocumentSnapshot | undefined, ParamsOf<Document>>>;

export declare function onDocumentUpdated<Document extends string>(document: Document, handler: (event: FirestoreEvent<Change<QueryDocumentSnapshot> | undefined, ParamsOf<Document>>) => any | Promise<any>): CloudFunction<FirestoreEvent<Change<QueryDocumentSnapshot> | undefined, ParamsOf<Document>>>;

export declare function onDocumentUpdated<Document extends string>(opts: DocumentOptions<Document>, handler: (event: FirestoreEvent<Change<QueryDocumentSnapshot> | undefined, ParamsOf<Document>>) => any | Promise<any>): CloudFunction<FirestoreEvent<Change<QueryDocumentSnapshot> | undefined, ParamsOf<Document>>>;

export declare function onDocumentDeleted<Document extends string>(document: Document, handler: (event: FirestoreEvent<QueryDocumentSnapshot | undefined, ParamsOf<Document>>) => any | Promise<any>): CloudFunction<FirestoreEvent<QueryDocumentSnapshot | undefined, ParamsOf<Document>>>;

export declare function onDocumentDeleted<Document extends string>(opts: DocumentOptions<Document>, handler: (event: FirestoreEvent<QueryDocumentSnapshot | undefined, ParamsOf<Document>>) => any | Promise<any>): CloudFunction<FirestoreEvent<QueryDocumentSnapshot | undefined, ParamsOf<Document>>>;

Were you able to successfully deploy your functions?

Yes

[google-oss-bot]

I couldn't figure out how to label this issue, so I've labeled it for a human to triage. Hang tight.

[johnnyoshika]

I'm also interested in this? In what scenario would event.data be undefined?

Background: event for onDocumentWritten is typed as:

FirestoreEvent<Change<DocumentSnapshot> | undefined, ParamsOf<Document>>

[exaby73]

There may be some documentation missing here. I'll label it as such