Transforming a Simple React App: Adding TypeScript and Unit Tests — My Learning Journey

Hello everyone,

I’m excited to share a personal project that documents my learning journey as I slowly improve a simple React app by adding TypeScript and unit tests. This project is inspired by 3 courses React — The Complete Guide 2025 (incl. Next.js, Redux), React & TypeScript — The Practical Guide, React Testing Library and Jest: The Complete Guide that I took on Udemy, and it’s been an incredible way to put the concepts I’ve learned into practice.

This project is not only an opportunity for me to improve my React skills but also to help others who are learning about React, testing, and TypeScript, or who may be looking for inspiration for their own projects. So, whether you’re a beginner or someone looking for a little direction, I hope you find this journey helpful!

Project Overview

The goal of this project was to take a basic React app and gradually improve it by:

1. Adding TypeScript for type safety and better development experience.
2. Introducing unit tests to ensure reliability and maintainability of the app.

I structured the project in three stages, each representing a key step in the development process:

1. initial_code: The original React app, before adding TypeScript or tests.
2. with_typescript: The same app with TypeScript added, without unit tests.