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)


In this chapter, we learned how to test pure functions written in TypeScript using Jest. We simply execute the function with the parameters we want to test, and use Jest's expect function chained with one of Jest's matcher functions, such as toBe, to validate the result.

We looked at how to interact with Jest's test runner, and how to apply filters so that only the tests we are focusing on are executed. We learned that testing React and TypeScript components is more involved than testing pure functions, but Jest and react-testing-library give us a great deal of help.

We also learned how to render a component using the render function, and how to interact with and inspect elements using various functions such as getByText and getLabelByText from react-testing-library.

We learned that we can easily test asynchronous interactions using the waitForElement function...