favorites data management - web service

favoriteRouter.js

const express = require('express');
const favoriteRouter = express.Router();
const authenticate = require('../authenticate');
const Favorite = require('../models/favorite');
const cors = require('./cors');

favoriteRouter.route('/')
.options(cors.corsWithOptions, (req, res) => res.sendStatus(200))
.get(cors.cors, authenticate.verifyUser, (req, res, next) => {
    Favorite.find({ user: req.user._id })
    .populate('user') //Adds fully hydrated user object
    .populate('campsites') //Adds fully hydrated campsite object
    .then(favorite => {
        res.statusCode = 200;
        res.setHeader('Content-Type', 'application/json');
        res.json(favorite);
    })
    .catch(err => next(err));
})
.post(cors.corsWithOptions, authenticate.verifyUser, (req, res, next) => {
    // Is there a favorite document for this user in the collection
    Favorite.findOne({ user: req.user._id })
    .then(favorite => {
        if (favorite) { //Yes the favorite document is in the collection...
            req.body.forEach(fav => {
                // Does the campsite not exist in the users favorites 
                if (!favorite.campsites.includes(fav._id)) {
                    favorite.campsites.push(fav._id); // no... so add the campsite to his/her favorites
                }
            });
            favorite.save()
            .then(favorite => {
                res.statusCode = 200;
                res.setHeader('Content-Type', 'application/json');
                res.json(favorite);
            })
            .catch(err => next(err));
        } else { //The favorite document is not in the campsites array
            Favorite.create({ user: req.user._id })
            .then(favorite => {
                req.body.forEach(fav => {
                    if (!favorite.campsites.includes(fav._id)) {
                        favorite.campsites.push(fav._id);
                    }
                });
                favorite.save()
                .then(favorite => {
                    res.statusCode = 200;
                    res.setHeader('Content-Type', 'application/json');
                    res.json(favorite);
                })
                .catch(err => next(err));
            })
            .catch(err => next(err));
        }
    }).catch(err => next(err));
})
.put(cors.corsWithOptions, authenticate.verifyUser, (req, res) => {
    res.statusCode = 403;
    res.end('PUT operation not supported on /favorites');
})
.delete(cors.corsWithOptions, authenticate.verifyUser, (req, res, next) => {
    Favorite.findOneAndDelete({ user: req.user._id })
    .then(favorite => {
        res.statusCode = 200;
        if (favorite) {
            res.setHeader('Content-Type', 'application/json');
            res.json(favorite);
        } else {
            res.setHeader('Content-Type', 'text/plain');
            res.end('You do not have any favorites to delete.');
        }
    })
    .catch(err => next(err));
});

favoriteRouter.route('/:campsiteId')
.options(cors.corsWithOptions, (req, res) => res.sendStatus(200))
.get(cors.cors, authenticate.verifyUser, (req, res) => {
    res.statusCode = 403;
    res.end(`GET operation not supported on /favorites/${req.params.campsiteId}`);
})
.post(cors.corsWithOptions, authenticate.verifyUser, (req, res, next) => {
    Favorite.findOne({user: req.user._id})
    .then(favorite => {
        if (favorite) {
            if (!favorite.campsites.includes(req.params.campsiteId)) {
                favorite.campsites.push(req.params.campsiteId);
                favorite.save()
                .then(favorite => {
                    res.statusCode = 200;
                    res.setHeader('Content-Type', 'application/json');
                    res.json(favorite);
                })
                .catch(err => next(err));
            } else {
                res.statusCode = 200;
                res.setHeader('Content-Type', 'text/plain');
                res.end('That campsite is already a favorite!');
            }
        } else {
            Favorite.create({ user: req.user._id, campsites: [req.params.campsiteId] })
            .then(favorite => {
                res.statusCode = 200;
                res.setHeader('Content-Type', 'application/json');
                res.json(favorite);
            })
            .catch(err => next(err));
        }
    })
    .catch(err => next(err));
})
.put(cors.corsWithOptions, authenticate.verifyUser, (req, res) => {
    res.statusCode = 403;
    res.end(`PUT operation not supported on /favorites/${req.params.campsiteId}`);
})
.delete(cors.corsWithOptions, authenticate.verifyUser, (req, res, next) => {
    Favorite.findOne({user: req.user._id })
    .then(favorite => {
        if (favorite) {
            const index = favorite.campsites.indexOf(req.params.campsiteId);
            if (index >= 0) {
                //To delete favorite, splice(start, deleteCount)
                favorite.campsites.splice(index, 1);
            }

            /* can alternatively use filter as below, instead of using indexOf/splice, 
               but make sure to use loose inequality OR do fav.toString() before comparing: */
            //favorite.campsites = favorite.campsites.filter(fav => fav.toString() !== req.params.campsiteId);

            favorite.save()
            .then(favorite => {
                console.log('Favorite Campsite Deleted!', favorite);
                res.statusCode = 200;
                res.setHeader('Content-Type', 'application/json');
                res.json(favorite);
            }).catch(err => next(err));
        } else {
            res.statusCode = 200;
            res.setHeader('Content-Type', 'text/plain');
            res.end('You do not have any favorites to delete.');
        }
    }).catch(err => next(err))
});

module.exports = favoriteRouter;