Use Hooks in React Redux

Use Hooks in React Redux

Posted on 10th November 2019

In my previous post I went through setting up Redux in a React app. Since then I learnt about using hooks as an alternative to the connect() Higher Order Component. In this post we will refactor the app we made in the previous post to use the Redux Hooks.

Getting Started

Before we start refactoring let’s check out the two hooks we are going to use.

  • useSelector - Allows us to get the state from the Redux store. This hook will be used to replace mapStateToProps in connect().
  • useDispatch - Allows us to dispatch out redux actions. This hook will be used to replace mapDispatchToProps in connect().

Refactoring the Controls Component

First lets remove the props, connect() Higher Order Component and mapStateToProps and mapDispatchToProps.

src/components/Controls.js

jsx
const Controls = () => {
return (
<div>
<button
onClick={() => actions.setUserId(user.userId - 1)}
disabled={user.userId <= 1 || user.isFetchingUser}
>
Previous
</button>
<button
onClick={() => actions.setUserId(user.userId + 1)}
disabled={user.userId >= 10 || user.isFetchingUser}
>
Next
</button>
</div>
);
};
export default Controls;

Then we need to import the two hooks from react-redux.

src/components/Controls.js

javascript
import { useSelector, useDispatch } from "react-redux";

To get the redux state, we need to use useSelector. useSelector needs a function as an argument where the redux state is the parameter and the return object is the state we need, similar to mapStateToProps. So use useSelector to declare the user inside the component.

src/components/Controls.js

javascript
const user = useSelector((state) => ({ user: state.user }));

The above line of code can be shortened to the following.

src/components/Controls.js

javascript
const user = useSelector((state) => state.user);

To call the redux actions, we need to declare the dispatch function in the component using the useDispatch hook. After that we can call out redux actions inside the dispatch function like we did in the getUser action.

src/components/Controls.js

javascript
const dispatch = useDispatch();

Just change all actions to run inside the dispatch function like this.

src/components/Controls.js

javascript
dispatch(setUserId(user.userId - 1));

In the end the Controls component should look like this.

src/components/Controls.js

jsx
import React from "react";
import { useSelector, useDispatch } from "react-redux";
import { setUserId } from "../redux/user/actions";
const Controls = () => {
const user = useSelector((state) => state.user);
const dispatch = useDispatch();
return (
<div>
<button
onClick={() => dispatch(setUserId(user.userId - 1))}
disabled={user.userId <= 1 || user.isFetchingUser}
>
Previous
</button>
<button
onClick={() => dispatch(setUserId(user.userId + 1))}
disabled={user.userId >= 10 || user.isFetchingUser}
>
Next
</button>
</div>
);
};
export default Controls;

Refactoring the Display Component

We need to refactor the Display component the same way we did the Controls component.

  • Remove all the connect() Higher Order Component related code.
  • Import useSelector and useDispatch.

src/components/Display.js

javascript
import { useSelector, useDispatch } from "react-redux";
  • Declare the user state using useSelector.

src/components/Display.js

javascript
const user = useSelector((state) => state.user);
  • Declare the dispatch function using useDispatch.

src/components/Display.js

javascript
const dispatch = useDispatch();
  • Change all Redux action to be called inside the dispatch function.

src/components/Display.js

javascript
dispatch(getUser(user.userId));

In the end the code for the Display component should look like this.

src/components/Display.js

jsx
import React from "react";
import { useSelector, useDispatch } from "react-redux";
import { getUser } from "../redux/user/actions";
const Display = () => {
const user = useSelector((state) => state.user);
const dispatch = useDispatch();
React.useEffect(() => {
dispatch(getUser(user.userId));
}, [user.userId]);
return (
<div>
<table>
<tbody>
<tr>
<td>ID: </td>
<td>{user.user.id}</td>
</tr>
<tr>
<td>Name: </td>
<td>{user.user.name}</td>
</tr>
<tr>
<td>Username: </td>
<td>{user.user.username}</td>
</tr>
<tr>
<td>Email: </td>
<td>{user.user.email}</td>
</tr>
</tbody>
</table>
</div>
);
};
export default Display;

Wrap Up

This is a sample of the setup we just did. If you think you missed something, feel free to check out the code.

Edit react-redux-hooks-starter

If you want to learn more about the hooks in react-redux, please check out the official documentation here.

If you found this post helpful please make sure to share it! 😊

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