im trying to display my data on my page by using async parallel but it spits out an error as a display

this would be my controller module , as i have already set up the router module

const Book = require('../models/book');
    const Author = require('../models/author');
    const Genre = require('../models/genre');
    const BookInstance = require('../models/bookinstance');
    
    const async = require('async');
    
    exports.index = (req, res) =>{
      async.parallel({
        book_count(callback) {
          Book.countDocuments({}, callback); // Pass an empty object as match condition to find all documents of this collection
        },
        book_instance_count(callback) {
          BookInstance.countDocuments({}, callback);
        },
        book_instance_available_count(callback) {
          BookInstance.countDocuments({ status:'Available' }, callback);
        },
        author_count(callback) {
          Author.countDocuments({}, callback);
        },
        genre_count(callback) {
          Genre.countDocuments({}, callback);
        }
      },
      (err, results) => {
        res.render('index', { title: 'Local Library Home', error: err, data: results });
      });
    };

Here im using pug as my rendering engine , it does display the title and the necessary elements but in the list section im trying to display my data which i have also included an if statement to indicate an error of retrieving the data, which it currently is. as if it was not connected to my database/model

extends layout

block content
  h1= title
  p Welcome to #[em LocalLibrary], a very basic website.

  h1 Dynamic content

  if error
    p Error getting dynamic content.
  else
    p The library has the following record counts:

    ul
      li #[strong Books:] !{data.book_count}
      li #[strong Copies:] !{data.book_instance_count}
      li #[strong Copies available:] !{data.book_instance_available_count}
      li #[strong Authors:] !{data.author_count}
      li #[strong Genres:] !{data.genre_count}

which i've done all the necessary connection to the database

var Book = require('./models/book')
var Author = require('./models/author')
var Genre = require('./models/genre')
var BookInstance = require('./models/bookinstance')


var mongoose = require('mongoose');
var mongoDB = userArgs[0];
mongoose.Promise = global.Promise;
var db = mongoose.connection;
db.on('error', console.error.bind(console, 'MongoDB connection error:'));