Elevating Your React Application with React Query: An Implementation Guide

Introduction

React is a JavaScript library used for building user interfaces. It allows developers to create reusable UI components and efficiently manage the application state. React is known for its declarative programming style and efficient rendering process, which allows developers to build performant applications.

Know: React Query

React Query is a library that simplifies fetching, caching, and updating server state in React applications. It provides a declarative API for fetching data and managing the cache. React Query uses caching and smart refetching to ensure that the data is always up to date and the UI is always responsive.

Here are some examples of how to use React Query in different scenarios:

1. Fetching data from an API endpoint:

import { useQuery } from 'react-query';

function App() {
  const { isLoading, error, data } = useQuery('todos', () =>
    fetch('https://jsonplaceholder.typicode.com/todos').then(res =>
      res.json()
    )
  );
  if (isLoading) return 'Loading...';
  if (error) return `An error has occurred: ${error.message}`;
  return (
    <ul>
      {data.map(todo => (
        <li key={todo.id}>{todo.title}</li>
      ))}
    </ul>
  );
}

In this example, we are fetching data from the JSONPlaceholder API endpoint and displaying a list of todos in the UI. The useQuery hook takes two arguments: a unique query key and a function that returns the data. The isLoading, error, and data variables are used to manage the state of the query.

2. Refetching data on a specific interval:

import { useQuery, useQueryClient } from 'react-query';

function App() {
  const queryClient = useQueryClient();
  useQuery('todos', () =>
    fetch('https://jsonplaceholder.typicode.com/todos').then(res =>
      res.json()
    ),
    {
      refetchInterval: 1000 * 60 // refetch every minute
    }
  );
  function handleRefresh() {
    queryClient.invalidateQueries('todos');
  }
  return (
    <div>
      <button onClick={handleRefresh}>Refresh</button>
    </div>
  );
}

In this example, we are refetching the data from the API endpoint every minute using the refetchInterval option in useQuery. We also have a button that allows the user to manually refresh the data by calling queryClient.invalidateQueries.

3. Caching data and updating it in the background:

import { useQuery, useMutation } from 'react-query';

function App() {
  const { isLoading, error, data } = useQuery('todos', () =>
    fetch('https://jsonplaceholder.typicode.com/todos').then(res =>
      res.json()
    )
  );
  const [mutate] = useMutation(
    todo =>
      fetch(`https://jsonplaceholder.typicode.com/todos/${todo.id}`, {
        method: 'PUT',
        headers: {
          'Content-Type': 'application/json'
        },
        body: JSON.stringify(todo)
      }).then(res => res.json()),
    {
      onSettled: () => {
        queryClient.invalidateQueries('todos');
      }
    }
  );
  function handleUpdate(todo) {
    mutate(todo);
  }
  if (isLoading) return 'Loading...';
  if (error) return `An error has occurred: ${error.message}`;
  return (
    <ul>
      {data.map(todo => (
        <li key={todo.id}>
          {todo.title}{' '}
          <button onClick={() => handleUpdate({ ...todo, completed: true })}>
            Complete
          </button>
        </li>
       )}
    </ul>
   )
  }

In conclusion, React Query is a powerful library that simplifies fetching, caching, and updating server state in React applications. With its declarative API, developers can easily manage complex data fetching scenarios, including caching, polling, and background updates. By using React Query, developers can create more efficient and responsive applications with less boilerplate code.

In the examples provided, we demonstrated how to use React Query in various scenarios, including fetching data from an API endpoint, refetching data on a specific interval, and caching data and updating it in the background. These examples show the versatility of React Query and how it can be used to handle different data fetching scenarios.

Overall, React Query is a valuable tool that every React developer should consider using in their projects. Its ease of use and flexibility make it a great choice for managing server state in modern web applications.