Use the React Query database plug-in to achieve automatic data synchronization

Use the React Query database plug-in to achieve automatic data synchronization

As front-end development becomes increasingly complex, data management becomes more and more important. React Query is a powerful database plug-in that provides us with convenient data status management and automatic synchronization functions. In this article, we will explore how to leverage React Query for automatic data synchronization and provide specific code examples.

1. Understanding React Query

React Query is a library focused on data management and synchronization. It is built on the basis of React and provides an easy-to-use API and powerful functions. The core concept of React Query is query. A query can request remote data, save the data locally, and automatically handle the loading, caching and synchronization of data. At the same time, React Query also provides clear data status management and error handling mechanisms. These allow us to process data more simply and efficiently.

2. Implementation of automatic data synchronization

1. Installing React Query

First, we need to install React Query in the project. It can be installed through npm or yarn:

npm install react-query
# 或者
yarn add react-query

After the installation is complete, import React Query in the application root component:

import { QueryClient, QueryClientProvider } from 'react-query';

2. Create QueryClient

In Create a QueryClient instance in the application to manage data requests and status:

const queryClient = new QueryClient();

and wrap it in QueryClientProvider to access the functions provided by QueryClient throughout the application:

ReactDOM.render(
  <QueryClientProvider client={queryClient}>
    <App />
  </QueryClientProvider>,
  document.getElementById('root')
);

3. Declare query

In components that need to use data, we can use the useQuery hook to declare a query. useQuery receives a query key and an asynchronous function for getting data from the remote server:

import { useQuery } from 'react-query';

function MyComponent() {
  const { data, isLoading } = useQuery('todos', fetchTodos);

  if (isLoading) {
    return <LoadingSpinner />;
  }

  return (
    <ul>
      {data.map((todo) => (
        <li key={todo.id}>{todo.title}</li>
      ))}
    </ul>
  );
}

async function fetchTodos() {
  const response = await fetch('/api/todos');
  const data = await response.json();
  return data;
}

In this example, we declare a query named "todos" that will call The fetchTodos function fetches to-do data from the server. While the data is loading, display a loading spinner; when loading is complete, render the to-do list.

4. Update data

React Query can automatically handle the loading and caching of data for us, but keeping the data real-time requires manual processing of data updates. We can use the useMutation hook to easily implement data update operations.

import { useMutation } from 'react-query';

function MyComponent() {
  const { data, isLoading } = useQuery('todos', fetchTodos);
  const mutation = useMutation(updateTodo);

  async function handleUpdate(id, status) {
    await mutation.mutateAsync({ id, status });
  }

  if (isLoading) {
    return <LoadingSpinner />;
  }

  return (
    <ul>
      {data.map((todo) => (
        <li key={todo.id}>
          {todo.title}
          <button onClick={() => handleUpdate(todo.id, 'completed')}>
            完成
          </button>
        </li>
      ))}
    </ul>
  );
}

async function updateTodo({ id, status }) {
  await fetch(`/api/todos/${id}`, {
    method: 'PUT',
    body: JSON.stringify({ status }),
    headers: { 'Content-Type': 'application/json' },
  });
}

In this example, we use the useMutation hook to declare a variable called mutation that contains a function that is called when the data is updated. Trigger the handleUpdate function by clicking the button, complete the corresponding to-do item, and send an update request to the server.

5. Automatically synchronize data

React Query also provides an automatic synchronization function, which allows us to automatically update the interface when the data changes. We can use the refetchOnMount and refetchInterval options in the useQuery configuration item to automatically trigger data query and update.

function MyComponent() {
  const { data, isLoading } = useQuery('todos', fetchTodos, {
    refetchOnMount: true,
    refetchInterval: 3000, // 每 3 秒自动更新一次数据
  });

  // ...
}

In this example, we set refetchOnMount to true, which means that a data query will be triggered when the component is mounted for the first time. At the same time, we set refetchInterval to 3000, which means that a data query will be triggered every 3 seconds to realize automatic update of data.

3. Summary

By using the React Query database plug-in, we can easily realize the automatic synchronization function of data. This article briefly introduces the basic usage of React Query and provides specific code examples. I hope this article can help you better understand and use React Query and play a role in actual projects.

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