WP_Customize_Manager::wp_die PHP Method

    protected function wp_die($ajax_message, $message = null)
    {
        if ($this->doing_ajax()) {
            wp_die($ajax_message);
        }
        if (!$message) {
            $message = __('Cheatin’ uh?');
        }
        if ($this->messenger_channel) {
            ob_start();
            wp_enqueue_scripts();
            wp_print_scripts(array('customize-base'));
            $settings = array('messengerArgs' => array('channel' => $this->messenger_channel, 'url' => wp_customize_url()), 'error' => $ajax_message);
            ?>
			<script>
			( function( api, settings ) {
				var preview = new api.Messenger( settings.messengerArgs );
				preview.send( 'iframe-loading-error', settings.error );
			} )( wp.customize, <?php 
            echo wp_json_encode($settings);
            ?>
 );
			</script>
			<?php 
            $message .= ob_get_clean();
        }
        wp_die($message);
    }