Difference between force-cache and libraries like react-query and SWR

The force-cache option in the fetch API and libraries like react-query and SWR handle caching differently and offer distinct features. Here’s how they differ:

force-cache Option in fetch

• Behavior: The force-cache option tells the browser to use a cached response if one is available. If there's no cache, it will fetch from the network.
• Scope: It operates at the HTTP request level, leveraging the browser's built-in cache mechanisms.
• Control: Provides limited control over caching beyond what the browser's HTTP cache supports. It doesn’t manage data invalidation or refetching beyond the standard cache headers.
• Use Case: Suitable for simple caching needs where you rely on the browser's default caching mechanisms and want to ensure cached data is used if available.

react-query and SWR

react-query and SWR are libraries designed to manage data fetching and caching in React applications. They provide a richer set of features compared to the simple force-cache option:

1. Advanced Caching:

   • react-query: Provides a sophisticated caching mechanism, allowing you to configure cache expiration, background refetching, and stale data handling.
   • SWR: Uses a cache-first strategy but offers more flexibility with features like revalidation and deduplication of requests.

2. Data Management:

   • react-query: Offers features like query invalidation, background data synchronization, and automatic retries on failure. It allows fine-grained control over when and how data is fetched and updated.
   • SWR: Focuses on the "stale-while-revalidate" strategy, allowing stale data to be served while new data is fetched in the background. This improves UX by providing instant responses while ensuring fresh data is loaded.

3. Automatic Refetching:

   • react-query: Can automatically refetch data at intervals, on window focus, or on network reconnection. This helps keep data up-to-date without manual intervention.
   • SWR: Similar functionality with options for revalidation on focus, network reconnection, or interval-based refetching.

4. Server-Side Data Handling:

   • react-query: Handles server-side data with features for prefetching data and server-side rendering (SSR) support.
   • SWR: Also supports SSR with the ability to prefetch data on the server and rehydrate it on the client.

5. Error Handling and Retries:

   • react-query: Includes built-in error handling, automatic retries, and configurable retry delays.
   • SWR: Provides error handling and automatic revalidation, with options for custom retry strategies.

Example Comparison

Using force-cache in fetch:

fetch('https://api.example.com/data', {
  cache: 'force-cache'
})
  .then(response => response.json())
  .then(data => console.log(data));

Using react-query:

import { useQuery } from 'react-query';

function ExampleComponent() {
  const { data, error, isLoading } = useQuery('dataKey', () =>
    fetch('https://api.example.com/data').then(res => res.json()), {
      staleTime: 5000, // Data is considered fresh for 5 seconds
      cacheTime: 10000, // Data remains in cache for 10 seconds after being stale
      refetchOnWindowFocus: true, // Refetch data when window is focused
    }
  );

  if (isLoading) return <div>Loading...</div>;
  if (error) return <div>Error!</div>;

  return <div>{JSON.stringify(data)}</div>;
}

Using SWR:

import useSWR from 'swr';

const fetcher = url => fetch(url).then(res => res.json());

function ExampleComponent() {
  const { data, error } = useSWR('https://api.example.com/data', fetcher, {
    refreshInterval: 5000, // Revalidate data every 5 seconds
    revalidateOnFocus: true, // Revalidate data when window is focused
  });

  if (!data) return <div>Loading...</div>;
  if (error) return <div>Error!</div>;

  return <div>{JSON.stringify(data)}</div>;
}