Caching is an essential part of improving performance in web applications. When working with GraphQL, caching responses can greatly reduce network latency and server load. In this article, we’ll explore how to cache GraphQL responses using the JavaScript Cache API.

Table of Contents

• Introduction to Caching
• Why Cache GraphQL Responses?
• Using the JavaScript Cache API
• Implementing GraphQL Response Caching
• Conclusion

Introduction to Caching

Caching is the process of storing data in a temporary storage to improve subsequent requests for the same data. By caching responses, we can avoid requesting the same data multiple times, thus reducing network traffic and improving application performance.

Why Cache GraphQL Responses?

GraphQL is a query language for APIs that allows clients to specify exactly what data they need. While this flexibility is powerful, it can also result in over-fetching data, leading to increased response sizes and slower network requests. By caching GraphQL responses, we can avoid re-fetching the same data for subsequent requests, resulting in faster response times and better user experience.

Using the JavaScript Cache API

The JavaScript Cache API provides a caching mechanism that can be used to store and retrieve responses. It allows us to cache both the request and response objects, making it suitable for caching GraphQL responses.

To start using the Cache API, we need to create a new Cache object using the caches.open() method:

const cacheName = 'graphql-responses';
const cacheVersion = 1;

caches.open(`${cacheName}-${cacheVersion}`)
  .then(cache => {
    // Cache API is ready to use
  });

Once we have access to the cache, we can use the cache.put() and cache.match() methods to store and retrieve responses respectively.

Implementing GraphQL Response Caching

To cache GraphQL responses, we can intercept outgoing requests and incoming responses. We can then store the responses in the cache using the URL of the request as the cache key. Here’s an example of how we can implement this in a JavaScript fetch interceptor:

self.addEventListener('fetch', event => {
  event.respondWith(
    caches.match(event.request)
      .then(response => {
        if (response) {
          return response;
        }
        return fetch(event.request)
          .then(response => {
            // Clone the response as it can be consumed only once
            const clone = response.clone();
            caches.open(`${cacheName}-${cacheVersion}`)
              .then(cache => cache.put(event.request, clone));
            return response;
          });
      })
  );
});

In this code snippet, we first check if the requested resource exists in the cache. If it does, we return the cached response. Otherwise, we fetch the resource from the network, cache the response, and return it to the client.

Conclusion

Caching GraphQL responses can significantly improve the performance of web applications. By leveraging the JavaScript Cache API, we can easily implement response caching and reduce network latency. Remember to use caching judiciously and consider cache invalidation strategies to ensure data freshness.

By adopting GraphQL response caching, we can create faster and more efficient applications, providing a better user experience. Happy caching!

References:

• MDN Web Docs - Cache API
• GraphQL - Caching #graphql #caching