I have deployed cloud function (Gen 2) that is supposed to be triggered each time a new document in “messages” collection is created in my Firestore DB. Than the “test” data field with hardcoded string is supposed to be added to this document. I can see that the function is actually triggered on new doc creation, but I am keep getting TypeError:

TypeError: Cannot read properties of undefined (reading 'value')
    at func (/workspace/node_modules/firebase-functions/lib/v2/providers/firestore.js:297:115)
    at /layers/google.nodejs.functions-framework/functions-framework/node_modules/@google-cloud/functions-framework/build/src/function_wrappers.js:113:25
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)

Cannot figure out what is the issue.

This is the code that is being executed:

const {logger} = require("firebase-functions");
const {onDocumentCreated} = require("firebase-functions/v2/firestore");
const {initializeApp} = require("firebase-admin/app");
const { getFirestore } = require("firebase-admin/firestore");

initializeApp();

const functionsRegion = "europe-west1";

exports.testtrigger = onDocumentCreated({region: functionsRegion}, "/messages/{documentId}", (event) => {
  logger.log("Inside test_trigger function");

  const test = "Function was triggered on new document creation.";
  const documentRef = getFirestore().doc(event.data.value.name); 
  return documentRef.set({ test }, { merge: true }); 
});

of I was also trying to return this:

return event.data.ref.set({test}, {merge: true});

which is basically same thing. Both fail.

Btw, I followed firebase docs and makeuppercase function gives me the same error.

From the docs:

// Listens for new messages added to /messages/:documentId/original
// and saves an uppercased version of the message
// to /messages/:documentId/uppercase
exports.makeuppercase = onDocumentCreated("/messages/{documentId}", (event) => {
  // Grab the current value of what was written to Firestore.
  const original = event.data.data().original;

  // Access the parameter `{documentId}` with `event.params`
  logger.log("Uppercasing", event.params.documentId, original);

  const uppercase = original.toUpperCase();

  // You must return a Promise when performing
  // asynchronous tasks inside a function
  // such as writing to Firestore.
  // Setting an 'uppercase' field in Firestore document returns a Promise.
  return event.data.ref.set({uppercase}, {merge: true});
});

How can I fix this issue?