Caching List.js Results – Reload filtered results on browser back button
As a web developer, you've likely encountered the challenge of creating a seamless user experience when working with dynamic content and filtering systems. One common scenario is when users apply filters to a list of items, such as products or properties, and then want to navigate back to the previous state of the filtered results.
In this blog post, we'll explore a technique that allows you to cache the filtered results of a List.js implementation and reload them when the user navigates back to the previous page using the browser's back button.
Understanding the Problem
When users apply filters to a list of items, the filtered results are often displayed on a separate page or within a dynamic content area. However, when the user navigates away from this page and then returns using the browser's back button, the default behavior is to reload the initial, unfiltered list of items.
This can be frustrating for users, as they have to reapply the filters to see the desired results. Additionally, if the filtering process involves server-side operations, such as database queries, this repeated process can lead to unnecessary load on the server and slower response times.
The Solution: Caching Filtered Results
To address this issue, we can leverage the window.history.pushState()
method to store the applied filter information in the URL. This way, when the user navigates back to the previous page using the browser's back button, we can retrieve the filter information from the URL and apply it to the List.js implementation, effectively reloading the cached filtered results.
Here's how you can implement this solution:
-
Store the Filter Information in the URL
When the user applies a filter, you'll need to update the URL to include the filter information. You can do this using the window.history.pushState()
method:
var option = document.getElementById('filter').value;
var url = `${window.location.href}?filter=${option}`;
window.history.pushState({}, '', url);
This will add the filter parameter to the URL, which will be stored in the browser's history.
-
Retrieve the Filter Information from the URL
When the page loads or when the user navigates back to the previous page, you'll need to check the URL for the filter parameter and apply it to the List.js implementation. You can use the URLSearchParams
API to extract the filter value from the URL:
// Get the filter value from the URL
const urlParams = new URLSearchParams(window.location.search);
const filterValue = urlParams.get('filter');
// Apply the filter to the List.js instance
myList.filter(function(item) {
return item.values().filter.toLowerCase().includes(filterValue.toLowerCase());
});
In this example, we're using the URLSearchParams
API to extract the filter
parameter from the URL. We then apply the filter to the List.js instance using the filter()
method.
-
Handle the Browser's Back and Forward Buttons
To ensure that the filtered results are properly reloaded when the user navigates using the browser's back and forward buttons, you'll need to listen for the popstate
event and apply the filter accordingly:
window.addEventListener('popstate', function() {
// Get the filter value from the URL
const urlParams = new URLSearchParams(window.location.search);
const filterValue = urlParams.get('filter');
// Apply the filter to the List.js instance
myList.filter(function(item) {
return item.values().filter.toLowerCase().includes(filterValue.toLowerCase());
});
});
This event listener will be triggered whenever the user navigates using the browser's back or forward buttons, and it will apply the filter based on the URL parameters.
By implementing this solution, you can ensure that users have a seamless experience when navigating through the filtered results of your List.js implementation. When they apply a filter and then navigate away, the filter information will be stored in the URL, and when they return using the back button, the filtered results will be reloaded automatically.
Considerations and Additional Features
Here are some additional considerations and features you can explore to enhance this solution:
-
Server-side Filtering: If your filtering process involves server-side operations, such as database queries, you can also cache the filtered results on the server side. This can improve performance and reduce the load on the server when users navigate back to the previous page.
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Pagination: If your list of items is paginated, you may need to also store the current page number in the URL, so that the correct page of filtered results is displayed when the user navigates back.
-
Multiple Filters: If your application supports multiple filters, you can extend the solution to handle more complex URL parameters, such as ?filter1=value1&filter2=value2
.
-
Fallback Behavior: If the user's browser does not support the window.history.pushState()
method, you can provide a fallback behavior, such as storing the filter information in a cookie or local storage.
-
Performance Optimization: Depending on the size of your list and the complexity of the filtering process, you may need to optimize the performance of your solution, such as debouncing the filtering function or implementing efficient data structures to store and retrieve the cached results.
-
WordPress Integration: If your website is built on WordPress, you can integrate this solution into your theme or plugin. This can be particularly useful for e-commerce websites, real estate listings, or any other WordPress-powered application that requires dynamic filtering and navigation.
By implementing this caching and history-based solution, you can create a more seamless and user-friendly experience for your List.js-powered applications, allowing users to navigate through filtered results with ease and without the frustration of reapplying filters.
Flowpoint.ai can help you identify all the technical errors that are impacting conversion rates on your website and directly generate recommendations to fix them, including issues related to caching and browser history management
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