Map Facet – change marker clusterer text color and size

<?php

// Add to your (child) theme's functions.php
// For more examples and explanation, see: 
// https://facetwp.com/help-center/facets/facet-types/map/#set-custom-marker-cluster-images

add_filter( 'facetwp_map_init_args', function( $settings ) {

  $clustericonsizes = array( 53, 56, 66, 78, 90 );  // specify icon image sizes. These are the default values.
  for ( $i = 1; $i <= 5; $i ++ ) {
    $settings['config']['cluster']['styles'][] = [
      'url'       => FACETWP_MAP_URL . '/assets/img/m' . $i . '.png', // directory, required. This is the default directory.
      'width'     => $clustericonsizes[ $i - 1 ], // required
      'height'    => $clustericonsizes[ $i - 1 ], // required
      'textColor' => '#ffffff', // white, optional
      'textSize'  => 16 // 16px, optional
    ];
  }

  return $settings;
} );