Web

To invalidate or empty the local cache in a web application, you can use the following techniques

1. Manually clearing the cache:

// Clear the entire cache

localStorage.clear();

sessionStorage.clear();<p></p>

2. Appending a cache-busting query parameter to the URL:

// Append a timestamp to the URL

window.location.href = <code>${window.location.origin}${window.location.pathname}?bust=${Date.now()}</code>;<p></p>

This technique forces the browser to fetch a new version of the resource by including a unique query parameter in the URL, which the browser will not cache.

3. Using the
   Cache-Control
   HTTP header:

// Set the Cache-Control header to prevent caching

fetch('/my-resource', {

  headers: {

    'Cache-Control': 'no-cache, no-store, must-revalidate'

  }

});

The Cache-Control   header can be used to control how the browser caches the response. Setting it to no-cache,  no-store , and  must-revalidate  will prevent the browser from caching the response.

4. Invalidating the cache using the unload  event:

window.addEventListener('unload', () => {

  // Invalidate the cache here

  localStorage.clear();

  sessionStorage.clear();

});

The  unload  event is fired when the user navigates away from the page, and can be used to invalidate the cache before the page is unloaded.

5. Using a service worker to control caching:

// In your service worker script

self.addEventListener('fetch', (event) => {

  event.respondWith(

    caches.open('my-cache').then((cache) => {

      return cache.match(event.request).then((response) => {

        if (response) {

          return response;

        }

        return fetch(event.request.clone()).then((response) => {

          cache.put(event.request, response.clone());

          return response;

        });

      });

    })

  );

});

Service workers allow you to have more fine-grained control over caching, including the ability to invalidate the cache programmatically.

The choice of technique will depend on your specific use case and the requirements of your application. For example, if you need to invalidate the cache for a specific resource, using a cache-busting query parameter or the Cache-Control  header might be the most appropriate approach. If you need to invalidate the cache for the entire application, using 

localStorage.clear()  or the unload  event might be more suitable.