Server - Cloud Functions

Helper functions for getting typed data from 2nd gen cloud function events.

Usage

import {
  getDataOnWritten,
  getBeforeAndAfterOnWritten,
  makeDocumentHandlerPath,
} from "@typed-firestore/server/functions";
import { onDocumentWritten } from "firebase-functions/v2/firestore";

export const handleBookUpdates = onDocumentWritten(
  { document: makeDocumentHandlerPath(refs.books) },
  async (event) => {
    /** Get only the most recent data */
    const data = getDataOnWritten(refs.books, event);

    /** Get the before and after the write event */
    const [before, after] = getBeforeAndAfterOnWritten(refs.books, event);
  },
);

The typed collection reference is passed only to facilitate type inference. The data is extracted from the event, not fetched from the ref.

makeDocumentHandlerPath builds the trigger path from the same typed reference and preserves the wildcard parameter name in the return type, so event.params.documentId is correctly typed downstream. Pass a custom name as the second argument when needed:

onDocumentCreated(
  { document: makeDocumentHandlerPath(refs.userSessions, "userId") },
  (event) => {
    /** event.params.userId is typed as string */
  },
);

Separate Import Path

The cloud function helpers are exported on @typed-firestore/server/functions, so that the firebase-admin and firebase-functions peer dependencies can both be optional:

• Import from @typed-firestore/server — requires firebase-admin, does not require firebase-functions
• Import from @typed-firestore/server/functions — requires firebase-functions, does not require firebase-admin

This only applies to JavaScript imports. TypeScript types do not affect this.

INFO

Only 2nd gen cloud function events are supported.

API Reference

Function	Description
getDataOnCreated	Get the data from a document create event
getDataOnWritten	Get the data from a document write event
getBeforeAndAfterOnWritten	Get the before and after data from a document write event
getBeforeAndAfterOnUpdated	Get the before and after data from a document update event
makeDocumentHandlerPath	Build a trigger path from a typed ref, preserving the wildcard param