post-filter-function.php

<?php

public function postFilter()
  {
    // Define custom post type and taxonomies
    $post_type = 'product';
    $taxonomies = array('brand', 'category');

    // Get the current page number
    $paged = (get_query_var('paged')) ? get_query_var('paged') : 1;

    // Define the query arguments
    $args = array(
      'post_type' => $post_type,
      'posts_per_page' => 10,
      'paged' => $paged,
      'tax_query' => array()
    );

    // Get the taxonomy terms from the URL
    foreach ($taxonomies as $taxonomy) {
      if (isset($_GET[$taxonomy]) && !empty($_GET[$taxonomy])) {
        $args['tax_query'][] = array(
          'taxonomy' => $taxonomy,
          'field' => 'slug',
          'terms' => $_GET[$taxonomy]
        );
      }
    }

    // Run the query
    $query = new WP_Query($args);

    // Check if there are any posts
    if ($query->have_posts()) {
      while ($query->have_posts()) {
        $query->the_post();
        // Display the post
      }
      // Pagenation
      $big = 999999999; // need an unlikely integer
    } else {
      // No Posts Found
    }
  }
}