Custom query vars filters problem with pagination

Question

I have multiple custom query vars to filter products with the pre_get_posts hook and the add_query_arg function.

All works fine except the pagination, when i navigate to the page number 5 (for example) without filtering and then i select one filter, if the products for that filter doesn't have 5 pages it will show nothing.

What most sites do is to return to first page when selecting a filter, but i don't know exactly how to do it.

I have this for a start, but of course it doesn't worked. I'll be appreciated if someone helps me.

if ( in_array(get_query_var('brand'), $wp_query->query_vars) ) {
   get_query_var('paged') = 1;
}

How i'm filtering:

function custom_query_vars_filter( $custom_vars ) {
  $custom_vars[] = 'marca';
    return $custom_vars;
  }
add_filter( 'query_vars', 'custom_query_vars_filter' );

function customize_main_query( $query ) {
if ( !is_admin() && $query->is_main_query() ) {

if ( is_product_category() ) {
  $query->set('posts_per_page', 3);    

  $marca= get_query_var('marca');

  $tax_query = array('relation' => 'AND');

  if ( $marca ) {
    $tax_query[] =  array(
      'taxonomy' => 'brands',
      'field' => 'slug',
      'terms' => $marca
    );
  }

  $query->set( 'tax_query', $tax_query );
} 
}
}
add_action( 'pre_get_posts', 'customize_main_query' );

Category archive page

$marca_arg = isset($marca) ? array($marca) : [];

foreach ($marcas_terms as $marca_term) {
   <div class="filtro-item">
      <a href="<?php echo (in_array($marca_term->slug, $marca_arg)) ? 
      esc_url(remove_query_arg('marca')) : esc_url(add_query_arg('marca', 
      "$marca_term->slug")); ?>"><span class="check- 
      filtro"></span><?php echo $marca_term->name; ?></a>
   </div>
}

Answer 1

The problem is the pagination parameter in the URL:

<a href="<?php echo (in_array($marca_term->slug, $marca_arg)) ? 
  esc_url(remove_query_arg('marca')) : esc_url(add_query_arg('marca', 
  "$marca_term->slug")); ?>">

Here we see that the marca term is being added and removed, but the pagination parameter isn't, but that's a part of the URL not a parameter

Instead, why not use the taxonomy archives and get_term_link? Then redirect if the marca parameter is present?

• You could eliminate the pre_get_posts changes
• the query var would no longer be necessary
• the pagination issue would disappear
• You can use taxonomy-brands.php in your theme
• You already have archives for this at example.com/brands/*term_name* just waiting for a custom template

They're already on your site, sitting there unused. Why rebuild something that's already there? If you're not keen on the URL you can change it in your taxonomy registration code via the rewrite option