How to save nested array in MongoDB using Mongoose and NodeJS

Question

Can anyone explain me how to save the nested array items into mongodb with mongoose and nodejs?.

Here is a schema I am using.

var demoSchema = ({
    "r_id": Number,
    "r_label": String,
    "entity": [{
        "d_label": String,
        "d_type": String
      }
    ]
})

And here is Nodejs function I am using to save the data into db

 app.route("/mypages/rooms")
  .post(function(req, res) {
   var db = mongoOp.demo();
   var response = {};
   req.checkBody("r_id", "Enter a valid r_id address.").notEmpty();
   req.checkBody("r_label", "Enter a valid label address.").notEmpty();

   var errors = req.validationErrors();
   if (errors) {
     console.log(errors);
     console.log(req.body);
     res.status(500);
     res.end('500 Server Error');
     //res.render('addrooms',{flag:1});
     return;
     } else {
         db.r_id = req.body.r_id;
         db.r_label = req.body.r_label;
         db.entity = req.body.entity;
         db.save(function(err) {
          if (err) {
           findfromdb(req, res, 2); //own function for implementation purpose
          } else {
           findfromdb(req, res, 1);
          }
        });
        //var middleVar = req.body.resources;
      //  console.log(middleVar[0].d_rgb);
     }
 });

Answer 1

set entity with array []

db.entity = [{}];

app.route("/mypages/rooms")
  .post(function(req, res) {
   var db = mongoOp.demo();
   var response = {};
   req.checkBody("r_id", "Enter a valid r_id address.").notEmpty();
   req.checkBody("r_label", "Enter a valid label address.").notEmpty();

   var errors = req.validationErrors();
   if (errors) {
     console.log(errors);
     console.log(req.body);
     res.status(500);
     res.end('500 Server Error');
     //res.render('addrooms',{flag:1});
     return;
     } else {
         db.r_id = req.body.r_id;
         db.r_label = req.body.r_label;
         db.entity = [{
                      "d_label": req.body.label_type,
                      "d_type": req.body.d_type
                     }];
         db.save(function(err) {
          if (err) {
           findfromdb(req, res, 2); //own function for implementation purpose
          } else {
           findfromdb(req, res, 1);
          }
        });
        //var middleVar = req.body.resources;
      //  console.log(middleVar[0].d_rgb);
     }
 });

---

The below operation adds the element label_type and d_type to entity array if they does not exist in the array, if they exists, then they won't be added

https://docs.mongodb.com/manual/reference/operator/update/addToSet/

Model.update(
    query, //  { _id: 1 }
    {
        $addToSet: {
            "enity": {
                "d_label": req.body.label_type,
                "d_type": req.body.d_type
            }
        }
    }
)

have a look at this answer

Pushing item to Mongodb collection array