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)

Mocking dependencies

Mocking a component's dependencies can make the component easier to test. However, if we mock too many things, is the test really verifying that the component will work in our real app?

Establishing what to mock is one of the hardest tasks when writing unit tests. There are some things that make a lot of sense to mock, though, such as REST APIs. A REST API is a pretty fixed contract between the frontend and backend. Mocking a REST API also allows our tests to run nice and fast.

In this section, we'll eventually learn how to mock REST API calls made with axios. First, though, we'll learn about Jest's function mocking feature.

Using a mock function in Jest

We are going to make another...