My mongoose model is not saving on the callback and I don't know why...


&&&Model&&&

var mongoose = require('mongoose');
var Schema = mongoose.Schema;

var CommentSchema = new Schema({
  body: {type: String, required: true, max: 2000},
  created: { type: Date, default: Date.now },
  flags: {type: Number, default: 0}
}, {
  writeConcern: {
    w: 0,
    j: false,
    wtimeout: 200
  }
});

var PostSchema = new Schema({
  body: {type: String, required: true, max: 2000},
  created: { type: Date, default: Date.now },
  flags: {type: Number, default: 0},
  comments: [{ type: Schema.Types.ObjectId, ref: 'Comment' }]
}, {
  writeConcern: {
    w: 0,
    j: false,
    wtimeout: 200
  }
});

var Post =  mongoose.model('Post', PostSchema);
var Comment = mongoose.model('Comment', CommentSchema)

module.exports = {
  Post: Post,
  Comment: Comment
}


&&&route&&&

var express = require('express');
var router = express.Router();
const fs = require('fs');
var model = require('../models/model');
// var getDirName = require('path').dirname;

/* GET home page. */
router.get('/', function(req, res, next) {
  res.render('index', { title: 'Express' });
});

router.post('/uploadPost', (req, res, next)=>{
  console.log('inside /uploadPost')
  // console.log('and value of req.body: ', req);
  console.log('value of req.files: ', req.files)
  console.log('value of req.body: ', req.body)

  var post = {
    body: req.body.post,
    created: Date.now(),
    flags: 0,
    comments: []
  }

  console.log('value of post: ', post)

  let postInstance = new model.Post(post)

  console.log('value of postInstance: ', postInstance)

  postInstance.save().then(post=>{
    console.log('value of post: ', post)
  }).catch( (e) => {
    console.log('There was an error', e.message);
  });

  res.json({return: 'return from /uploadPost'})
})

module.exports = router;