We will examine creating a new post using the "CREATE POST" route within the postsRoutes.js file. This route is responsible for handling the creation of a post and saving it to the data source (database/posts.json).

Route Definition

The code below defines the "CREATE POST" route using router.post():

• This route is configured to handle HTTP POST requests to the root path /;
• It utilizes the validatePostData middleware, which ensures that the data sent in the request body is valid before proceeding.

Data Validation Middleware

Before delving into the route's logic, we must create a data validation middleware. This middleware ensures that the data sent in the request body is valid before attempting to create a new post.

• The validatePostData function extracts the username, postTitle, and postContent from the request body;
• It checks whether these fields are present. If any of them are missing (!username, !postTitle, or !postContent), it responds with a 400 (Bad Request) status code and an error message indicating missing required fields;
• If the data is valid, the middleware calls next(), allowing the request to continue to the route handler (the "CREATE POST" route in this case).

With the data validation middleware in place, let's continue with the "CREATE POST" route logic.

New Post Data

To create a new post, we generate a unique ID using Date.now().toString(). Additionally, we extract the username, postTitle, and postContent from the request body.

Add the New Post to the Database

The following steps detail how the new post is added to the database:

• The existing data is read from the JSON file using the asynchronous readData function, as previously explained;
• The new post is added to the data array;
• The updated data array is then written back to the JSON file to save the newly created post.

Sending a Response

Upon successful creation of the new post, a success response is sent to the client. The response includes a status code of 201 (Created) and the details of the newly created post in JSON format.

Error Handling

We wrap the route code in a try-catch block to handle potential errors during data retrieval or request processing. Any errors that occur are logged to the console for debugging purposes:

Complete code of the postsRoutes.js file at this step

Complete code of the validateData.js file