Зміст курсу

Backend Development with Node.js and Express.js

1. Introduction to Node.js and Backend Development

The Role of the Backend in Web Development What is Node.js?Key Advantages of Using Node.js Installing Node.js Creating Your First Node.js App Challenge: Build Your First Node App Key Takeaways

2. Building Console Applications with Node.js

Introduction to Console Applications in Node.js What are Console Applications?Working with the File System in Node.js Challenge: File System Operations Building Command Line Interface (CLI) Apps Using the Commander Module for CLI Apps Working with the Readline Module Building a Guessing Game Console App Managing Directories in Node.js Directory Inspection Tool Summary of Console Applications in Node.js

3. Developing Web Applications with Express.js

Introduction to Express.js in Web Development Why Use Express.js for Web Development?Understanding HTTP Requests Setting Up an Express.js Application Creating and Managing Routes in Express.js Testing APIs with Postman Introduction to Middleware in Express.js Using Built-in Middleware in Express.js Creating Custom Middleware Summary of Key Express.js Concepts

4. Building REST APIs with Node.js and Express.js

Introduction to REST API Development Core Concepts of REST APIs Setting Up the Project Structure Defining the Entry Point of the API Building the GET All Posts Endpoint Building the GET Post by Id Endpoint Building the CREATE Post Endpoint Building the UPDATE Post by Id Endpoint Building the DELETE Post by Id Endpoint Running and Testing the REST API Final Thoughts and Next Steps

Building the UPDATE Post by Id Endpoint

We will research how to update an existing post using the "UPDATE POST BY ID" route within the postsRoutes.js file. This route handles the updating of a post based on its unique ID.

Route Definition

The code below defines the "UPDATE POST BY ID" route using router.put():

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This route is configured to handle HTTP PUT requests, specifically for updating posts;
It includes a parameterized :id in the route path to identify the post to be updated;
The validatePostData middleware is added to ensure data validation before proceeding. The logic of the validatePostData middleware remains the same as in the previous step.

Obtaining Data from the Request

Here, we extract the necessary data from the request, including the post ID and the updated post content:

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The post ID is extracted from the request parameters, making it available for further processing. The :id parameter from the route URL is captured using req.params.id;
The username, postTitle, and postContent are extracted from the request body.

Update the Post in the Database

Updating an existing post involves several steps, as outlined below:

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We read the existing data from the JSON file using the asynchronous readData function, as explained earlier;
The postIndex variable stores the index of the post to be updated in the data array by comparing post IDs;
If the post is not found (i.e., postIndex === -1), a 404 (Not Found) response with an error message is returned to the client;
To update the post data, we merge the existing post data (...data[postIndex]) with the updated data (...updatedData). This ensures that only the specified fields are updated and existing data is retained;
Finally, the updated data array is written back to the JSON file to save the changes made to the post.

Sending a Response

Upon successful post update, a JSON response is sent to the client. The response includes a status code of 200 (OK), indicating a successful update and the updated post data.

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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:

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Complete code of the postsRoutes.js file at this step

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