We can use our anonymous or named functions as middleware. To do so, we would export our functions by calling module.exports in routes/actors.js and routes/movies.js:

Let's take a look at our routes/actors.js file. At the top of this file, we require the Mongoose schemas we defined before:

var Actor = require('../models/actor');

This allows our variable actor to access our MongoDB using mongo functions such as find(), create(), and update(). It will follow the schema defined in the file /models/actor.

Since actors are in movies, we will also need to require the Movie schema to show this relationship by the following.

var Movie = require('../models/movie');

Now that we have our schema, we can begin defining the logic for the functions we described in endpoints. For example, the endpoint GET /actors/:id will retrieve the actor with the corresponding ID from our database. Let's call this function getOne(). It is defined as follows:

getOne: function(req,...