How can I update a nested field given another nested field value with Mongoose?

Question

I'm creating an endpoint which is intended to update an answer of a question already answered before, but I'm having troubles accessing that field on my Mongoose schema.

The schema I'm working with responds to this JSON example:

{
    "pollId":15,
    "userId":13,
    "name":"poll name",
    "description":"poll desc.",
    "status":"poll status",
    "created":"2020-10-13",
    "modified":"2020-10-16",
    "sections":[
        {
            "sectionIndex":1,
            "sectionTitle":"section title",
            "sectionDescription":"section desc.",
            "questions":[
                {
                    "questionIndex":1,
                    "questionTitle":"quest. title ",
                    "questionType":"quest. type",
                    "value":"quest. answer", //<- This could be the field to update
                    "mandatory":true,
                    "multiline":false,
                    "adornment":"",
                    "restrictions":{"min":0,"max":10},
                    "options":[{"option":"option 1"},{"option":"option 2"},{"option":"option 3"}]
                },
                {
                    "questionIndex":2,
                    "questionTitle":"quest. title ",
                    "questionType":"quest. type",
                    "value":"quest. answer", //<- This could be the field to update
                    "mandatory":true,
                    "multiline":false,
                    "adornment":"",
                    "restrictions":{"min":0,"max":10},
                    "options":[{"option":"option 1"},{"option":"option 2"},{"option":"option 3"}]
                }]
        },
        {
            "sectionIndex":2,
            "sectionTitle":"section title",
            "sectionDescription":"section desc.",
            "questions":[
                {
                    "questionIndex":1,
                    "questionTitle":"quest. title ",
                    "questionType":"quest. type",
                    "value":"quest. answer", //<- This could be the field to update
                    "mandatory":true,
                    "multiline":false,
                    "adornment":"",
                    "restrictions":{"min":0,"max":10},
                    "options":[{"option":"option 1"},{"option":"option 2"},{"option":"option 3"}]
                },
                {
                    "questionIndex":2,
                    "questionTitle":"quest. title ",
                    "questionType":"quest. type",
                    "value":"quest. answer", //<- This could be the field to update
                    "mandatory":true,
                    "multiline":false,
                    "adornment":"",
                    "restrictions":{"min":0,"max":10},
                    "options":[{"option":"option 1"},{"option":"option 2"},{"option":"option 3"}]
                }
              ]
}

What I want to achieve:

Access the field value on the question with questionIndex:X on the section with sectionIndex:Y and update said value.

What I've tried so far:

So far I tried this on my endpoint controller:

{
    let query = {pollId: req.body.pollId, sectionIndex: req.body.sectionIndex, questionIndex: req.body.questionIndex}
    pollSchema.findOneAndUpdate(query,{$set :{value: req.body.value}},{new:true},function(err)
    {
       res.status(200).send({message:"updated"});  
       (err)=>
        { 
            res.status(500).send(err);
            console.log(err);
        }
    
    });
}

But this doesn't seems to work...

Additional Information:

I'm testing the enpoint with Postman and storing the documents on a MongoDB Atlas Cluster.

If you need more information feel free to ask. Thanks in advance

Answer 1

Ok, so I managed to figure it out.

I'll leave the answer if someone is interested

pollSchema.findOneAndUpdate(pollId: req.body.pollId, "sections.questions.questionIndex": req.body.questionIndex,{$set: {"sections.$[s].questions.$.value": req.body.value}},{arrayFilters: [{"s.sectionIndex": req.body.sectionIndex}]})

For more information go to:

$ operator

$[]

$[< identifier >]

I'd recommend to read these articles completely, but you'll get the idea just with the sections on those hyperlinks