Wordpress | WordPress Editor Custom Image Shortcode

//functions.php
function customimage_shortcode( $atts, $content = null ) {
    extract( shortcode_atts( array(
        'url'    => '',
        'text'   => '',
    ), $atts ) );
    $imgurl = $url ? $url : $imgurl;
    $content = $text ? $text : $content;
    if ( $url ) {
        foreach ( $link_attr as $key => $val ) {
            if ( $val ) {
                $link_attrs_str .= ' ' . $key . '="' . $val . '"';
            }
        }
        return '<figure class="customimage"><img src="' . $imgurl . '"/><figcaption>' . do_shortcode( $content ) . '</figcaption></figure>';
        
    }
}
add_shortcode( 'customimage', 'customimage_shortcode' );
function register_customimage( $buttons ) {
   array_push( $buttons, "", "customimage" );
   return $buttons;
}
function add_plugin_customimage( $plugin_array ) {
    $plugin_array['customimage'] = get_template_directory_uri() . '/js/customimage.js';
   return $plugin_array;
}
function my_customimage_shortcode() {
   if ( ! current_user_can('edit_posts') && ! current_user_can('edit_pages') ) {
      return;
   }
   if ( get_user_option('rich_editing') == 'true' ) {
      add_filter( 'mce_external_plugins', 'add_plugin_customimage' );
      add_filter( 'mce_buttons', 'register_customimage' );
   }
}
add_action('init', 'my_customimage_shortcode');

// customimage.js
(function() {
   tinymce.create('tinymce.plugins.customimage', {
      init : function(ed, url) {
         ed.addButton('customimage', {
            title : 'Custom Image',
            image : url+'/customimage.svg',
            onclick : function() {
                var title = prompt("Text", "Call to Action");
                var target = prompt("Target", "_blank");
                ed.execCommand('mceInsertContent', false, '[customimage url="'+href+'" text="'+title+'"]');
            }
         });
      },
      createControl : function(n, cm) {
         return null;
      },
      getInfo : function() {
         return {
            longname : "Custom Image",
            author : 'Otowui.com',
            authorurl : 'https://www.otowui.com',
            version : "1.0"
         };
      }
   });
   tinymce.PluginManager.add('customimage', tinymce.plugins.customimage);
})();