TypeError: Cannot read property 'toString' of undefined on function convertDocToObj(doc)

[senapahlevi]

hello mr.bassir please helpme to finish your course without any error, before i followed your part 14 tutorial my code run well connect and can read data.js with mongoDB but when i followed your code on part 14 im stuck getting error
here the output

`import mongoose from "mongoose";

const connection = {};

async function connect() {
if (connection.isConnected) {
console.log("already connected");
return;
}
if (mongoose.connections.length > 0) {
connection.isConnected = mongoose.connections[0].readyState;
if (connection.isConnected === 1) {
console.log("use previous connection");
return;
}
await mongoose.disconnect();
}
//delete useCreateIndex, useNewUrlParser, useUnifiedTopology because mongoose 6.00 not used anymore
const db = await mongoose.connect(process.env.MONGODB_URI, {});
console.log("new connection");
connection.isConnected = db.connections[0].readyState;
}

async function disconnect() {
if (connection.isConnected) {
if (process.env.NODE_ENV === "production") {
await mongoose.disconnect();
connection.isConnected = false;
} else {
console.log("not disconnected");
}
}
}

function convertDocToObj(doc) {
doc._id = doc._id.toString();
doc.createdAt = doc.createdAt.toString();
doc.updatedAt = doc.updatedAt.toString();
return doc;
}

const db = { connect, disconnect, convertDocToObj };
export default db;`

[senapahlevi]

hello any body help me please, when i cloned part 14 repository then npm install all library and package still get same error like these

[jessicagallagher]

I'm also getting errors with the convertDocToObj(doc) function. I'm getting undefined as stated above, and I'm also getting an error saying TypeError: Cannot read properties of null (reading '_id') traced to the function itself in db.js. As the OP did, I've followed the tutorial step by step and confirmed that my code is the exact same as the repo. I searched for some answers before posting the issue, but nothing was really helpful in solving or explaining the error.