MetaBox Select Advanced Ajax

MetaBoxClass.php

<?php

class MetaBoxClass {

  function __construct(){

    // Set MetaBox
    add_filter('rwmb_meta_boxes', array(&$this, 'my_meta_box'));

    // Add new field type
    add_action('init', array(&$this, 'prefix_load_SelectAdvancedAjax_type'));

    // Ajax call
    add_action('wp_ajax_get_my_options', array(&$this, 'get_my_options'));
    add_action('wp_ajax_nopriv_get_my_options', array(&$this, 'get_my_options'));

  }

  public function my_meta_box($meta_boxes){

    $select_advanced_ajax_id = "_my_select";

    $meta_boxes[] = array(
      'title'  => 'Infos',
      'post_types' => array( 'page' ),
      'fields' => array(
        array(
          'name' => 'My Super Select',
          'id'   => "_my_super_select",
          'type' => 'select_advanced_ajax',
          'sanitize_callback'   => 'none',
          'js_options' => array (
            'ajax' => array(
              'url' => '/wp-admin/admin-ajax.php',
                'dataType' => 'json',
                'type' => 'post',
                'data' => [
                  'action' => 'get_my_options',
                ],
                'delay' => '250',
              ),
            'minimumInputLength' => 0,
            'allowClear' => true, 
            'placeholder' => 'Select an option',
          ),
        ),
      ),    
    );

    return $meta_boxes;

  }

  public function get_my_options(){

    $results = [
      'results' => [],
    ];

    for($i = 1; $i <= 10; $i++):

      $results['results'][] = array(
        'id' => $i,
        'text' => 'Option '.$i,
      );

    endfor;

    wp_send_json($results);

    wp_die();

  }

  public function prefix_load_SelectAdvancedAjax_type(){
    require 'RWMB_Select_advanced_ajaxField.php';
  }

}

new MyMetaBox();

RWMB_Select_advanced_ajax_Field.php

<?php

class RWMB_Select_advanced_ajax_Field extends RWMB_Select_Advanced_Field {

  public static function html( $meta, $field ) {

    $options                     = self::transform_options( $field['options'] );
		$attributes                  = self::call( 'get_attributes', $field, $meta );
		$attributes['data-selected'] = $meta;
		$walker                      = new RWMB_Walker_Select( $field, $meta );
    
    $attributes['class'] .= ' rwmb-select_advanced';

		$output                      = sprintf(
			'<select %s>',
			self::render_attributes( $attributes )
		);
		if ( ! $field['multiple'] && $field['placeholder'] ) {
			$output .= '<option value="">' . esc_html( $field['placeholder'] ) . '</option>';
		}
		$output .= $walker->walk( $options, $field['flatten'] ? -1 : 0 );
		$output .= '</select>';
		$output .= self::get_select_all_html( $field );

    $interfaceValue = rwmb_meta($field['id'] .'-interface');

    // Hidden field for remember the content of the selector
    $output .= '<input
      type="hidden"
      id="'. $field['id'] .'-interface"
      name="'. $field['id'] .'-interface"
      value=\''. $interfaceValue .'\' />';

    // JavaScript to handle the select (see select2 documentation)
    $output .= '<script type="text/javascript">
      jQuery(function($){
        var $interface = $("#'. $field['id'] .'-interface");
        var $field = jQuery("#'. $field['id'] .'");
        $field.on("change", function(){
          var $this = $(this);
          var value = $this.find(":selected").val();
          var text = $this.find(":selected").text();
          var data = "";
          if(value != ""){
            data = JSON.stringify({ value : value, text : text });
          }
          $interface.val(data);
        });
        if($interface.val() != ""){
          var data = JSON.parse($interface.val());
          var newOption = new Option(data.text, data.value, true, true);
          $field.append(newOption);
        }
      });
    </script>';

		return $output;
  }

  public static function save( $new, $old, $post_id, $field ) {
    
    // Force saving our hidden field
    update_metadata( 'post', $post_id, $field['id'].'-interface', $_POST[$field['id'].'-interface']);
    
    parent::save($new, $old, $post_id, $field);
    
  }

}