Overview

This filter lets you modify a facet’s HTML output.

Parameters

  • $output | string | The facet HTML
  • $params | array | An associative array of facet settings (see below)
How to use custom PHP code?
PHP code can be added to your (child) theme's functions.php file. Alternatively, you can use the Custom Hooks add-on, or a code snippets plugin. More info
$params = [
  'facet' => [
    'name' => 'my_facet',
    'type' => 'checkboxes',
    'source' => 'tax/category',
    // any other facet-specific settings
  ],
  'values' => [], // available for checkbox & dropdown facets
  'selected_values' => [ 100, 101 ]
];

Examples

Add a class to a facet type

The following code adds a “form-control” CSS class to all Dropdown facets:

How to use custom PHP code?
PHP code can be added to your (child) theme's functions.php file. Alternatively, you can use the Custom Hooks add-on, or a code snippets plugin. More info
add_filter( 'facetwp_facet_html', function( $output, $params ) {
  if ( 'dropdown' == $params['facet']['type'] ) {
    $output = str_replace( 'facetwp-dropdown', 'facetwp-dropdown form-control', $output );
  }
  return $output;
}, 10, 2 );

Translate facet choices

To translate a facet choice based on the currently set language, you can use this hook as follows. This example is for when you are using WPML, with the Multilingual add-on installed.

For Polylang, use lines 9-10 instead of lines 5-6.

Make sure to replace my_facet_name in line 2 with the name of your facet.

How to use custom PHP code?
PHP code can be added to your (child) theme's functions.php file. Alternatively, you can use the Custom Hooks add-on, or a code snippets plugin. More info
add_filter( 'facetwp_facet_html', function( $output, $params ) {
  if ( 'my_facet_name' == $params['facet']['name'] ) {

    // For WPML:
    $current = ( !empty( FWP()->facet->http_params['lang'] ) ) ? FWP()->facet->http_params['lang'] :  apply_filters( 'wpml_current_language', null );
    $default = apply_filters('wpml_default_language', NULL );

    // For Polylang, use these 2 lines instead of 2 above
    //$current = ( !empty( FWP()->facet->http_params['lang'] ) ) ? FWP()->facet->http_params['lang'] : pll_current_language();
    //$default = pll_default_language();

    $replace_values = [];
    $replace_values['nl'] = [
      'Belgium' => 'België',
      'Bulgaria' => 'Bulgarije'
    ];
    if ( $current != $default && !empty( $replace_values[$current] ) ) {
      $default_values = [];
      $new_values = [];
      foreach ( $replace_values[$current] AS $replace_value => $replacement ) {
        $default_values[] = $replace_value;
        $new_values[] = $replacement;
      }
      $output = str_replace( $default_values, $new_values, $output );
    }
  }

  return $output;
}, 10, 2 );

Alternatively, you can do the same using the facetwp_facet_display_value hook, or the facetwp_facet_render_args hook. With this last hook, you can not only directly translate (and re-order) the choices, but also change specific or all facet choice labels into __() translatable strings. These can then be translated with a translation plugin or a gettext filter.

Also see this section on the Multilingual page for more info about the recommended way to translate facet choices, which is to translate the facet’s data source itself (the custom field or taxonomy terms).

More examples

See also

Last updated: February 10, 2026