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Folafolu Osilaja
Folafolu Osilaja

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My Experience Building a Basic REST API with Express.js and Joi Validation

Recently, I worked on an assignment to build a simple REST API using Node.js and Express.js. The goal was to create an API for managing courses, supporting CRUD operations (Create, Read, Update, Delete). While the basic setup was straightforward, implementing Joi validation was an interesting addition that improved data integrity and error handling.

Setting Up the Express Server

I started by setting up an Express server and defining a list of courses as in-memory data. Implementing routes for fetching all courses, retrieving a specific course by ID, adding new courses, updating existing ones, and deleting them provided a solid foundation for API development.

Key Challenges & Fixes

Handling Missing Data in POST and PUT Requests

Without validation, API users could send empty or malformed data, leading to unexpected behavior. To fix this, I integrated Joi, a popular schema validation library for JavaScript.

Adding Joi for Input Validation

Joi allowed me to define rules, ensuring course names were at least 3 characters long and required. Implementing it in POST and PUT requests helped catch invalid inputs before they caused issues in the application.

What I Learned

  • Express.js makes REST API development simple, but careful handling of parameters and request-response flow is crucial.
  • Joi is a powerful validation tool that helps enforce data integrity before processing user inputs.
  • Meaningful error handling enhances API usability by providing clear feedback when something goes wrong.

Conclusion

This assignment reinforced best practices in backend development, from structuring API endpoints to improving data validation and error handling. Moving forward, I plan to explore middleware for logging, authentication, and database integration to make APIs more scalable and robust.

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