1imageModel.js

import mongoose from 'mongoose';

const { Schema } = mongoose;
mongoose.Promise = global.Promise;

const imageSchema = new Schema({
    title: String,
    categories: [{type: Schema.Types.ObjectId, ref: 'Category'}],
    description: String,
    path: String,
    createdAt: {type: Date, default:Date.now},
    isDeleted: {type: Boolean, default: false}
});

const Image = mongoose.model('Image', imageSchema);
export default Image;

2categoryModel.js

import mongoose from 'mongoose';

const { Schema } = mongoose;
mongoose.Promise = global.Promise;

const categorySchema = new Schema({
    name: {type:String, ref:'Image'},
    createdAt: {type:Date, default: Date.now},
    isDeleted: {type: Boolean, default: false}
});

const Category = mongoose.model('Category', categorySchema);
export default Category;

3imageController.js

imageController.getAll = (req,res)=>{
    db.Image.find({}).populate('categories')
        .then( images =>{
            res.json(images)
        })
};

4Output.json

[
  {
    "_id": "590787970a477629a4dd45d3",
    "title": "Bra Girl",
    "description": "Girl portrait",
    "path": "http://res.cloudinary.com/amazecpk/image/upload/v1493665693/acu1vuajlg1rklzfqduk.png",
    "__v": 0,
    "isDeleted": false,
    "createdAt": "2017-05-01T19:08:07.441Z",
    "categories": [
      {
        "_id": "58fc3d9fa5ed6233486cc977",
        "name": "Personal",
        "__v": 0,
        "isDeleted": false,
        "createdAt": "2017-04-23T05:37:35.352Z"
      },
      {
        "_id": "58fc3dc0a5ed6233486cc979",
        "name": "Portraits",
        "__v": 0,
        "isDeleted": false,
        "createdAt": "2017-04-23T05:38:08.734Z"
      }
    ]
  }
]