This module will teach you about React Hooks and its advance concepts such as useDependency Pattern.

React Development for Professionals

In this module, you will learn how to use React Hooks as opposed to class components, which will help you achieve better code composition, code reuse, and unit testing.

We will start by reviewing what React Hooks are and why we need them. Then we will dive into the Hooks API, how to manage application state globally, and how to create custom hooks. In the second half, we will get into unit testing and how to work with the popular useDependency Pattern. By the end of this module, you will have the confidence to write enterprise-level React Hooks code.

A Deep Dive into React Hooks

Unit testing for React Hooks is an interesting topic. It requires a different approach compared to testing normal React components.

Assume you have a custom hook `useContent` to return some content value.

```
const useContent = () => {
  const [state] = useState('something');
  return state;
};
```

Write a simple test for the above hook using Jest `expect` like this.

```
test('useContent hook returns correct content', () => {
  expect(useContent()).toBe('something');
});

```

When this test is run, the following error occurs:

> Invalid hook call. Hooks can only be called inside of the body of a function component.

Oops. 

That's right. You tried to call a React Hook using `expect` which is not a React component. The next few lessons will explore different approaches to testing React Hooks. 

Why can’t you use the traditional way of unit testing with React Hooks?


Introduction

Getting Started with React Hooks

React Hooks API

Advanced: Deep Dive into useEffect Hook

Managing Global State with Hooks

Create Your Own Hooks

Unit Testing for React Hooks

Advanced: useDependency Pattern with Hooks

Conclusion

Introduction