Book Image

Learn React with TypeScript 3

By : Carl Rippon
Book Image

Learn React with TypeScript 3

By: Carl Rippon

Overview of this book

React today is one of the most preferred choices for frontend development. Using React with TypeScript enhances development experience and offers a powerful combination to develop high performing web apps. In this book, you’ll learn how to create well structured and reusable react components that are easy to read and maintain by leveraging modern web development techniques. We will start with learning core TypeScript programming concepts before moving on to building reusable React components. You'll learn how to ensure all your components are type-safe by leveraging TypeScript's capabilities, including the latest on Project references, Tuples in rest parameters, and much more. You'll then be introduced to core features of React such as React Router, managing state with Redux and applying logic in lifecycle methods. Further on, you'll discover the latest features of React such as hooks and suspense which will enable you to create powerful function-based components. You'll get to grips with GraphQL web API using Apollo client to make your app more interactive. Finally, you'll learn how to write robust unit tests for React components using Jest. By the end of the book, you'll be well versed with all you need to develop fully featured web apps with React and TypeScript.
Table of Contents (14 chapters)

Testing components

Unit testing a component is challenging because a component has dependencies such as the browser's DOM and the React library. How exactly can we render a component in our test code before we do the necessary checks? How can we trigger DOM events when coding a user interaction, such as clicking a button?

We'll answer these questions in this section, by implementing some tests on the ContactUs component we created in our React shop.

Creating a basic component test

We are going to start by creating a unit test to verify that submitting the Contact Us form without filling in the fields results in errors being displayed on the page:

  1. We are going to implement a unit test on the ContactUs component...