Mongoose & node js to fetch record from two schema based on id's

Question

I am beginner in mean stack development now am trying to get records from two schema by common id but am getting only the records from 2nd schema not from the first schema my code is below

kindly tell me the possible solution to get records from two collections

models/project.js

var mongoose = require("mongoose"),
 Schema = mongoose.Schema,
objectId = mongoose.Schema.ObjectId;
var projectSchema = Schema({
  name    : {type: String, required : true},
  designation    : {type: String, required : true},
  status    : {type: Number, required : true},
  berief_text : {type: String, required : true},
  Projectimage : [{ type: Schema.Types.ObjectId, ref: 'Projectimage' }]
});

var projectsimageSchema = Schema({
  projectId : { type: String, ref: 'Project' },
  imageLocation    : {type: String, required : true }
});

var Projectimage  = mongoose.model('Projectimage', projectsimageSchema);
var Project = mongoose.model('Project', projectSchema);

module.exports = {
    Projectimage: Projectimage,
    Project: Project
};

project.controller.js

var express = require("express"),
 router = express.Router(),
 project = require("../../models/project.js");
 var multer = require('multer');
var fs = require('fs');
   router.get("/", function(req, res) {
     project.Projectimage
    .find({ projectId: '58d8f7c2e4b90b0ee461e8f5' })
    .populate('Projectimage')
    .populate('Project')
    .exec(function (err, Projectimage) {
      if (err) return res.send(err);
      console.log('The are an array: ', Projectimage);
res.send(Projectimage)
    });
    });

module.exports = router;

This is my output

/* 1 */
{
    "_id" : ObjectId("58d8f7c2e4b90b0ee461e8f6"),
    "imageLocation" : "uploads\\project_images\\1490614210385download.jpg",
    "projectId" : "58d8f7c2e4b90b0ee461e8f5",
    "__v" : 0
}

/* 2 */
{
    "_id" : ObjectId("58d8f7c2e4b90b0ee461e8f7"),
    "imageLocation" : "uploads\\project_images\\1490614210390download (3).jpg",
    "projectId" : "58d8f7c2e4b90b0ee461e8f5",
    "__v" : 0
}

expected output

[{
    "_id" : ObjectId("58d8f7c2e4b90b0ee461e8f5"),
    "name" : "first project",
    "designation" : "chated Accountent",
    "berief_text" : "hi welcome to projects",
    "status" : 1,
    "Projectimage" : [

   /* 1 */
    {
        "_id" : ObjectId("58d8f7c2e4b90b0ee461e8f6"),
        "imageLocation" : "uploads\\project_images\\1490614210385download.jpg",
        "projectId" : "58d8f7c2e4b90b0ee461e8f5",
        "__v" : 0
    }

    /* 2 */
    {
        "_id" : ObjectId("58d8f7c2e4b90b0ee461e8f7"),
        "imageLocation" : "uploads\\project_images\\1490614210390download (3).jpg",
        "projectId" : "58d8f7c2e4b90b0ee461e8f5",
        "__v" : 0
    }



],
    "__v" : 0
}

]

this is the output for the first answer

The are an array:  [ { _id: 58d8f7c2e4b90b0ee461e8f5,
    name: 'first project',
    designation: 'chated Accountent',
    berief_text: 'hi welcome to projects',
    status: 1,
    __v: 0,
    Projectimage: [] } ]

Answer 1

you should rather do this

project.Project
.findOne({ _id: '58d8f7c2e4b90b0ee461e8f5' })
.populate('Projectimage')
.exec(function (err, project) {

})

you were rather calling a .find on the Projectimage subdocument instead of Project