updating document inside array in mongoose - node.js

Question

I want to update my answer object inside answers array. I am using following schema
const mongoose = require("mongoose");
const { ObjectId } = mongoose.Schema;
const questionSchema = new mongoose.Schema(
{
postedBy: {
type: ObjectId,
required: true,
ref: "User",
},
question: {
type: String,
required: true,
},
photo: {
data: String,
required: false,
},
answers: [
{
userId: { type: ObjectId, ref: "User" },
answer: String,
},
],
questionType: {
data: String,
required: false,
},
},
{ timeStamps: true }
);
module.exports = mongoose.model("Question", questionSchema);
I am using updateOne method to update my answer in my db. Can anyone explain what is missing here. I am been trying to solve this since hours
exports.updateAnswer = (req, res) => {
const questionId = req.body.questionId;
const answerId = req.body.answerId;
Question.findOne({ _id: questionId }).exec((err, question) => {
if (err) {
res.status(400).json({
error: errorHandler(err),
});
return;
}
if (!question) {
res.status(400).json({
error: "question not found",
});
return;
}
});
Question.updateOne(
{ _id: answerId },
{
$set: {
"answers.$.answer": "This is update answer. My name is Ravi Dubey",
},
},
{ new: true },
(err, success) => {
if (err) {
res.status(400).json({
error: errorHandler(err),
});
}
res.json({
msg: "answer updated successfully",
success,
});
}
);
};
My result is coming successful but answer is not updating in db.
I am confused on Question.updateOne method.
Any help appreciated.

Answer 1

If you trying to query based on id of one of the documents in the answers array then instead of {_id: answerId} you need to provide {'answers._id': answerId}. And also if you need the updated document as result then you should use the findOneAndUpdate method.
Question.findOneAndUpdate(
{ "answers._id": answerId },
{ $set: { "answers.$.answer": "some answer" } },
{ new: true },
(err, data) => {
// handle response
}
);