array push of records obtained from mongo db - arrays

Question

In MEAN stack, I am trying to store the records obtained from mongo db in an array, but I am not able to store the record in an array.
This is my code, I am trying to push the records obtained from projectimage to fulldetails[] array, but it failed. Suggest me the possible solution to store the mongo db records to array
var express = require("express"),
router = express.Router(),
project = require("../../models/project.js"),
projectimage = require("../../models/projectimages.js"),
var details=data;
var fulldetails=[];
for (var i = 0; i < details.length; i++) {
var prjct_id=details[i]._id;
console.log('below'+i);
fulldetails.push(details[i]);
projectimage.findOne({projectId: prjct_id}, function(err, data){
fulldetails.concat(data);
});
console.log(fulldetails);
return false;
}

Answer 1

I think what do you want is to get an array from your Mongo collection, correct me if I am wrong.
I am also assuming that Mongo query runs successfully, and returns the records correctly. then you can use toArray function to get array in callback.
// let's say Furniture is your collection
let furniture = Furniture.find({});
let details = [];
furniture.toArray((err, array) => {
if (err) return;
details = array; // now details has your collections' documents
});
For more refer this
Let me know if this is not what you were looking for.

Answer 2

I think you're trying to get a flat array of full details. If my assumption is correct, you could try my solution here:
var fulldetails=[];
for (var i = 0; i < details.length; i++) {
var prjct_id=details[i]._id;
projectimage.find({projectId: prjct_id}).toArray(function(err, data){ //convert data to array first
console.log(data);
fulldetails.concat(data); // concat data to fulldetails to get a flat array
});
}