Firebase Cloud functions - Failed to load function definition from source: Restful Endpoints - Failed to add the endpoint defined

I am using firebase cloud functions with typescript in node 16.14.

My index.ts look like this:

    import { FunctionParser } from "firebase-backend";
    exports = new FunctionParser({rootPath: __dirname, exports, 
    verbose:true}).exports;

Here is the addEvent.endpoint.ts:

import { Request, Response } from "express";
import { Endpoint, RequestType } from "firebase-backend";
// import * as functions from "firebase-functions";

const fs = require('firebase-admin');
const serviceAccount = require('./key.json');
fs.initializeApp({
 credential: fs.credential.cert(serviceAccount)
});

const db = fs.firestore();

export default new Endpoint(
    "addEvent",
    RequestType.POST,
    (request: Request, response: Response) => {
        
        const message = request.body["message"];

        db.collection("events").doc("adkakjagjh").set("message", message);
        
        return response.status(201).send({
            message: message
        });
    }
)

I have the following file structure as below.

My cloud functions worked just recently but some change that I am not aware of has made them error out with the following error for just this 1 endpoint "addEvent.endpoint.ts": Error: Failed to load function definition from source: Failed to generate manifest from function source: Error: Restful Endpoints - Failed to add the endpoint defined in C:/Development/EventFeeder/Backend/Firebase/functions/lib/users/restful/addEvent.endpoint.js to the users Api.

How can I fix this issue? I am not sure what I need to try because the error message is not that specific about the problem's root cause. I did not find any post about this particular problem.

I try to run the functions with "npm run build && firebase emulators:start --only functions" and "firebase emulators:start"

The issue disappear when I remove the addEvent.endpoint.ts file