How to Use a Data Fetching Tool to Manage Server State in Your React Application
Tags: react, javascript, webdev, productivity
Published: 2023-06-06 07:17:00

Managing server state in a React application is a crucial aspect of building robust web applications. One of the key challenges in this process is efficiently fetching data from the server and handling it in a way that ensures a smooth user experience. In this article, we will explore how to use a data fetching tool to manage server state effectively in your React application.

## Why Use a Data Fetching Tool?

Before diving into the implementation details, let's understand why using a data fetching tool can be beneficial. While it is possible to fetch data from a server using built-in JavaScript functions like `fetch()` or `axios`, these low-level APIs require handling a lot of boilerplate code, such as managing loading and error states, caching, pagination, and more. A data fetching tool abstracts away these complexities, providing a simpler and more convenient way to fetch data.

## Introducing React Query

React Query is a popular data fetching library that simplifies the process of fetching, caching, synchronizing, and updating server state in React applications. It offers a powerful set of features and an intuitive API, making it an excellent choice for managing server state.

## Installation

To get started, install React Query using npm or yarn:

```sh
npm i @tanstack/react-query

#or

yarn add @tanstack/react-query
```

## Basic Usage

Once React Query is installed, you can start using it in your React components. Let's walk through a basic example to demonstrate how to fetch and manage server state with React Query.

First, import the necessary functions and components from the React Query library:

```jsx
import { useQuery } from '@tanstack/react-query';
```

Next, define a function that fetches data from the server. In this example, we'll fetch a list of users:

```js
const fetchUsers = async () => {
  const response = await fetch('/api/users');
  const data = await response.json();
  return data;
};
```

Now, use the `useQuery` hook to fetch the data and manage the server state:

```jsx
const UsersList = () => {
  const { data, isLoading, error } = useQuery('users', fetchUsers);

  if (isLoading) {
    return <p>Loading...</p>;
  }

  if (error) {
    return <p>Error: {error.message}</p>;
  }

  return (
    <ul>
      {data.map((user) => (
        <li key={user.id}>{user.name}</li>
      ))}
    </ul>
  );
};
```

In the code snippet above, the `useQuery` hook takes two arguments: a unique query key (`'users'`) and the function (`fetchUsers`) responsible for fetching the data. The hook automatically manages the loading state (`isLoading`), error state (`error`), and caches the data (`data`). This ensures that the UI automatically updates when the data changes.

## Advanced Features

React Query provides various advanced features to handle more complex scenarios:

### Mutations

Mutations allow you to modify data on the server. React Query simplifies the process of sending requests, handling loading and error states, and updating the cache after a mutation. Here's an example:

```jsx
import { useMutation } from 'react-query';

async function(userData) {
  const response = await fetch('/api/users', {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
    },
    body: JSON.stringify(userData),
  });

  const data = await response.json();
  return data;
};

const CreateUserForm = () => {
  const { mutate, isLoading, error } = useMutation(createUser);

  const handleSubmit = (event) => {
    event.preventDefault();
    const formData = new FormData(event.target);
    const userData = Object.fromEntries(formData.entries());
    mutate(userData);
  };

  return (
    <form onSubmit={handleSubmit}>
      <input type="text" name="name" placeholder="Name" />
      <input type="email" name="email" placeholder="Email" />
      <button type="submit" disabled={isLoading}>
        {isLoading ? 'Creating...' : 'Create User'}
      </button>
      {error && <p>Error: {error.message}</p>}
    </form>
  );
};
```

In the code snippet above, the `useMutation` hook is used to define a mutation operation (`createUser`). The `mutate` function triggers the mutation and automatically handles loading and error states.

### Query Invalidation and Refetching

React Query provides a mechanism to invalidate and refetch data based on various triggers, such as user actions or time intervals. For example, you can refetch data every 5 seconds:

```jsx
const { data } = useQuery('users', fetchUsers, {
  refetchInterval: 5000,
});
```

Or manually trigger a refetch:

```jsx
const { data, refetch } = useQuery('users', fetchUsers);

function handleRefresh() {
  refetch();
};
```

These features give you fine-grained control over when and how data should be fetched and updated.

## Why Not Use the Flux Pattern?

- **Complexity**: Implementing the Flux pattern requires defining actions, action creators, reducers, and managing the store. This adds additional layers of complexity to your codebase, especially as the application grows in size and complexity.

- **Boilerplate code**: The Flux pattern often involves writing a significant amount of boilerplate code to handle actions, reducers, and store updates. This can lead to code bloat and make the application harder to maintain.

- **Data fetching and caching**: While Flux patterns provide mechanisms for managing state, they don't offer built-in solutions for data fetching and caching. You would need to handle these aspects separately, potentially resulting in duplication of code and added complexity.

- **Synchronizing server state with client state**: With Flux patterns, synchronizing the server state with the client state can be a manual and error-prone process. React Query simplifies this by automatically caching and synchronizing the server state with the UI.

React Query, on the other hand, provides a streamlined and efficient way to manage server state without the need for additional patterns or libraries. It abstracts away the complexities of data fetching, caching, and state management, allowing you to focus more on building UI components and delivering a great user experience.

## Alternatives

While React Query is a powerful data fetching tool, it's worth mentioning that there are other excellent options available in the React ecosystem. Two popular alternatives to React Query are SWR and RTK Query.

When it comes to choosing between React Query, SWR, and RTK Query, it ultimately depends on your specific requirements and preferences. Each tool has its own strengths and focuses on different aspects of data fetching and state management.

**<u>React Query</u>** is a powerful and flexible solution with a comprehensive set of features, making it suitable for a wide range of applications. It offers excellent caching capabilities, mutation support, and seamless integration with React.

**<u>SWR</u>**, on the other hand, shines when it comes to providing fast and efficient data fetching with its Stale-While-Revalidate approach. It's lightweight, easy to use, and works well with Next.js.

**<u>RTK Query</u>** is a great choice if you're already using Redux or prefer a more opinionated and integrated solution. It offers powerful caching and state management capabilities while leveraging the Redux ecosystem.

Ultimately, it's recommended to evaluate the specific requirements of your project, explore the documentation and examples of each tool, and choose the one that best fits your needs. All three options—

## Conclusion

> Using a data fetching tool can greatly simplify the process of managing server state in your React applications. It provides a powerful set of features, such as caching, mutations, and query invalidation, which can significantly enhance the performance and user experience of your application. By leveraging React Query, you can focus more on building your UI components and less on handling the complexities of server state management.

Keep building! 🚀