Remove query strings from WordPress assets to allow caching.

When caching, most assets with a query string are not cached, so this will hamper your efforts and decrease performance.

What is a query string? A query string is the ?something= parameter in the URL.

WordPress automatically adds version query strings to your CSS & JS assets when they are loaded.

If you look at your website source, you’ll see something like <link rel="stylesheet" src="https://domain.com/wp-content/themes/themename/style.css?ver=1.2.3" type="text/css" media="all" />.

Notice the ?ver=123, that’s the query string blocking your caching.

How do we do it?

Removing is relatively easy, let’s take a look. Simply add the following function to your functions.php file.

<?php
if ( ! function_exists( 'uncoverwp_remove_query_strings' ) ) :
    /**
     * Remove query strings from
     * assets for caching
     */
    function uncoverwp_remove_query_strings( $src )
    {
        return remove_query_arg( 'ver', $src );
    }
    add_filter( 'script_loader_src', 'uncoverwp_remove_query_strings' );
    add_filter( 'style_loader_src', 'uncoverwp_remove_query_strings' );
endif;

This simply adds our function to remove the query argument on the script and style loader tags, thus removing the query string from the assets URLs.

Conclusion.

A very easy way to boost your sites performance and allow full caching of assets.