Hidden Ninja Forms form field that captures PMPro membership level

ninja_forms_field_membership_level.php

<?php
/*
 * Add a hidden field in Ninja Forms to capture Membership Level (if user is logged in).
 *
 * For Ninja Forms version 3 and higher.
 */
// Create Membership Level field for Ninja Forms
add_filter( 'ninja_forms_register_fields', function( $fields ) {
	$fields['pmpromembershiplevel'] = new PmproMembershipLevel;
	return $fields;
} );
class PmproMembershipLevel extends NF_Abstracts_Input {			
	protected $_name = 'pmpromembershiplevel';
	protected $_nicename = 'Membership Level';
	protected $_section = 'userinfo';
	protected $_icon = 'eye-slash';
	protected $_type = 'hidden';
	protected $_templates = 'hidden';
	protected $_wrap_template = 'wrap-no-label';
	protected $_settings_only = array(
		'key', 'label', 'admin_label'
	);
	public function __construct() {
		parent::__construct();
		$this->_nicename = __( 'Membership Level', 'ninja-forms' );
		$this->_settings[ 'label' ][ 'width' ] = 'full';
	}
}
// Set value for pmpromembershiplevel field
add_filter( 'ninja_forms_render_default_value', 'nf_default_value_membership_level' , 10 , 3);
function nf_default_value_membership_level( $default_value, $field_type, $field_settings ) {
	global $current_user;
	// Get the current user's membership level object.
	if ( function_exists( 'pmpro_getMembershipLevelForUser' ) ) {
		$level = pmpro_getMembershipLevelForUser( $current_user->ID );
	} else {
		$level = false;
	}
	// Get the current user's membership level name.
	if ( ! empty( $level ) ) {
		$current_membership_level_name = $level->name;
	} else {
		$current_membership_level_name = false;
	}
	if ( 'pmpromembershiplevel' == $field_type && in_array( 'pmpromembershiplevel', $field_settings ) && ! empty( $current_membership_level_name ) ) {
		$default_value = $current_membership_level_name;
	}
	return $default_value;
}