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)

Chapter 11: Unit Testing with Jest

  1. Let's say we are implementing a Jest test and we have a variable called result, which we want to check isn't null. How can we do this with Jest matcher functions?
  1. Let's say we have variable called person that is of type IPerson:
interface IPerson {
id: number;
name: string;

We want to check that the person variable is { id: 1, name: "bob" }. How can we do this with Jest matcher functions?

expect(person).not.toBeEqual({ id: 1, name: "bob" });
  1. Is it possible to carry out our check in the last question with a Jest snapshot test? If so how?


  1. We have implemented a component called CheckList, which renders text from an array in a list. Each list item has a checkbox so that the user can select list items. The component has a function prop...