FacetWP ACF custom field options

facetwp-acf.php

<?php
add_filter('facetwp_facet_html', 'de_acf_facetwp_options', 10, 2);
function de_acf_facetwp_options($output, $params)
{
//    map field key
    $fieldKeys = [
        'custom_field_name_1' => 'field_{key}',
    ];

//    get clean custom field source
    $source = str_replace('cf/', '', $params['facet']['source']);
    if (in_array($params['facet']['type'], ['checkboxes', 'dropdown']) && preg_match('/^cf\//', $params['facet']['source']) && in_array($source, array_keys($fieldKeys)) && $object = get_field_object($fieldKeys[$source])) {
//        create selectbox
        $select = '<select class="facetwp-dropdown">';
        $select .= '<option value>' . $params['facet']['label_any'] . '</option>';
        foreach ($params['values'] as $value) {
            $select .= '<option value="' . $value->facet_value . '">' . $object['choices'][$value->facet_value] . ' (' . $value->counter . ')</option>';
        }
        $select .= '</select>';

        return $select;
    }

    return $output;
}