How to post request for a particular field of array in mern stack

Question

The code does not add answer in answers array......pls explain how to write the correct way to implement it? The 'id' is of the question, used for params.

Schema:

const QuestionSchema = new mongoose.Schema({
    qtitle:{
        type:String,
        required:true
    },
    descofq:{
        type:String,
        required:true
    },
    pic:{
        type:String,
        default:"no photo"
    },
    answers:[
        {
            answer:{
                type:String,
                required:false
            },
            picofa:{
                type:String,
                default:"no photo"
            },
            postedBy:{
                type:mongoose.Schema.Types.ObjectId,
                ref:"USER"
            }
        }
    ]
    }
})

POST request :

router.post('/answer/:id',authenticate,(req,res)=>{
    Question.findById(req.params.id).then(question=>{
        question.answers.answer = req.body.answer;
        question.save().then(result=>{
            res.json(result)
        }).catch(err=>{
            res.status(400).send(err);
        })
    }).catch(err=>{
        res.status(200).send(err);
    })
})

I also tried question.answers.answer.push(answer); where the answer in brackets will be acquired from req.body, but this also didn't work.

Answer 1

Answers field is an array you should specify which answer inside answers array

router.post('/answer/:id',authenticate,(req,res)=>{
    Question.findById(req.params.id).then(question=>{
        question.answers.push(req.body.answers);
        question.save().then(result=>{
            res.json(result)
        }).catch(err=>{
            res.status(400).send(err);
        })
    }).catch(err=>{
        res.status(200).send(err);
    })
})

Example: req.body.answers = { answer: "bla bla..", picofa: "bla bla", postedBy: userId }

Another solution:

router.post('/answer/:id',authenticate,(req,res)=>{
    Question.findById(req.params.id).then(question=>{
        question.answers[0].answer = req.body.answer;
        question.save().then(result=>{
            res.json(result)
        }).catch(err=>{
            res.status(400).send(err);
        })
    }).catch(err=>{
        res.status(200).send(err);
    })
})