Storing API responses in the cache with the JavaScript Cache API

23 Oct 2023

Caching API responses can greatly improve the performance and user experience of your web applications. The JavaScript Cache API provides a simple way to store and retrieve responses from the cache. In this blog post, we will explore how to use the Cache API to store API responses in the browser’s cache.

Introduction to the Cache API
Storing API Responses in the Cache
Retrieving Cached Responses
Refreshing the Cache
Conclusion

Introduction to the Cache API

The Cache API is a part of the Service Worker technology that allows web developers to store assets and API responses in a cache. It works on a key-value basis, where each cache entry has a unique key and a corresponding value. The Cache API provides methods to interact with the cache, such as adding, retrieving, and deleting entries.

Storing API Responses in the Cache

To store API responses in the cache, we can follow these steps:

Open a cache using the caches.open() method.

caches.open('api-cache')
  .then(cache => {
 // Add API response to the cache
  });

Use the cache.put() method to add the API response to the cache.

const url = 'https://api.example.com/data';
fetch(url)
  .then(response => {
 cache.put(url, response.clone());
 return response;
  });

Now the API response is stored in the cache and can be retrieved later.

Retrieving Cached Responses

To retrieve cached responses from the cache, we can use the cache.match() method. Here’s an example:

const url = 'https://api.example.com/data';
caches.open('api-cache')
  .then(cache => {
    cache.match(url)
      .then(response => {
        if (response) {
          // Use the cached response
        } else {
          // Fetch the response from the network
        }
      });
  });

If a cached response is found, it can be used immediately. Otherwise, the response can be fetched from the network.

Refreshing the Cache

To keep the cache up to date, you can periodically refresh the cached responses. One approach is to use a background sync or a service worker to update the cache when there is an internet connection.

Here’s an example of using a service worker to refresh the cache:

self.addEventListener('fetch', event => {
  event.respondWith(
    caches.open('api-cache')
      .then(cache => {
        return cache.match(event.request)
          .then(response => {
            const fetchPromise = fetch(event.request)
              .then(networkResponse => {
                cache.put(event.request, networkResponse.clone());
                return networkResponse;
              });

            return response || fetchPromise;
          });
      })
  );
});

In this example, the service worker intercepts network requests and checks the cache first. If a cached response is found, it is returned immediately. Otherwise, the request is made to the server, and the response is stored in the cache for future use.

Conclusion

The JavaScript Cache API provides an easy way to store API responses in the cache, improving the performance and offline capabilities of web applications. By combining the Cache API with other web technologies like service workers, you can create robust and efficient caching strategies for your applications.

Make sure to utilize the Cache API in your next project to enhance the user experience and optimize the performance of your web applications.

References:

#javascript #caching

Table of Contents

Introduction to the Cache API

Storing API Responses in the Cache

Retrieving Cached Responses

Refreshing the Cache

Conclusion