Testing is one of the most important skills you can learn and hone as a Software Developer. It improves your bug-free code's quality and makes the program much less likely to have bugs. On top of that, it's very convenient to make refactoring possible, which improves your lines of code maintainability!

Few people emphasize the importance of testing when teaching Software Development. Yet, it’s a skill that can set you apart from other developers. Your critical thinking and reasoning skills will improve as you get used to testing code. The vast world of Software Testing falls into two types: manual and automated. Yet, you might have also heard about unit, continuous integration, and snapshot testing. This article will focus on popular testing frameworks TypeScript developers use to test and perform automated testing. Let’s put it to the test!

What is Unit Testing?

Unit testing libraries consider small units to ensure that everything does what you expect. What is critical here is that there must not be any communication between the unit and any other piece of code. So, the test mustn't connect to a database or receive compatible API calls or any external dependency injections. That allows you to address bugs in your configuration files quickly. In this manner, unit testing improves your code's quality and maintainability. Now, let's talk about why TypeScript rocks in unit tests!

What is TypeScript Unit Testing?

We've already discussed how powerful TypeScript is and how it compares to JavaScript. It provides all the power and potential of JavaScript but with extra benefits. That's why you have heard it is a superset of JavaScript. Some additional benefits include Integrated Development Environment (IDE) support, static typing, better code readability, and developer tooling. As a result, you're less likely to make mistakes, which means you might not need as many tests. TypeScript comes with all the greatness of JavaScript and its frameworks. That, of course, includes all the testing frameworks. You'll be happy to hear that Visual Studio supports the most popular ones! Now, let's finally talk about the testing frameworks we recommend.

Best TypeScript Unit Testing Frameworks

Jest for TypeScript Unit Testing

Let's begin with one of the most popular typescript frameworks, Jest, which is among our preferred ones for a reason. It's perfect for testing React web apps. Also, it’s easy to integrate with other powerful JavaScript tools to develop a product. Those tools include Babel, Webpack, and ESLint. And the best part is that it also works excellently with Node.js and Vue.js. Jest requires zero configuration and can execute multiple tests in parallel so that it might be a great choice for larger projects. That streamlines the testing process to a large extent, making it fast and smooth. That's why our stellar team of software developers loves working with it.

Vitest for TypeScript Unit Testing

Vitest was a popular framework in 2022. It comes with all of Jest's key built-in features and power and is better suited for modern products. It includes workspace and out-of-the-box TypeScript support. You can think of Vitest as an improved version of Jest. It even has Jest-compatible Snapshot along with Expect and coverage. Plus, Vitest makes migrating from Jest a straightforward process. Integrating it into a Vite project is also very straightforward.

Storybook for TypeScript Unit Testing

This one goes for our UX/UI-savvies! Storybook strongly focuses on UI components in isolation, its main difference from Jest and Vitest. One of the key features is its stunning visual interface. You can inspect and debug UI components without logic or app context interference. It's instrumental in a world with many user interfaces.

It has that name because it can save every subtle UI variation as a "story." You can access those stories and use them in development and testing. Storybooks help simplify the increasing complexity of web development. Plus, when it comes to TypeScript, Storybook also provides a zero-configuration setup.

Mocha for TypeScript Unit Testing

You probably know this one. Also, you may notice it has more complex projects compared to the previous frameworks. However, many developers love Mocha for multiple reasons. Mocha is a robust framework that allows you to work with an external assertion library, such as Chai. Moreover, tests run sequentially, offering more flexibility. Apart from that, it supports asynchronous testing and furthers Test-Driven Development. One last perk we can’t overlook is the stunning and accurate reports it provides. They come in handy when tracking test coverage and failing tests.

Tip: If you’re using Mocha or Jasmine, you must type ts-node to add TypeScript support to your test suite.  On the other hand, if you're using Jest, you must start with ts-Jest. Additionally, you would likely place source JS/TS in the src folder and test files in the test folder.

Final Thoughts

Our preferred framework is the Jest test suit because it’s highly effective for running parallel testing units of code. Since most developers already use it, you will likely need some familiarity when joining a project. Contrariwise, Vitest strongly focuses on cutting-edge products. Mocha and Storybook are other popular choices, as they have core features that may help guarantee top-notch code quality for Full-Stack JavaScript projects. So, choosing the unit testing tool may be a great idea, depending on the development process requirements!