private static function get_constants_data() {

		$data = array(
			'LLMS_REMOVE_ALL_DATA'                 => 'undefined',
			'LLMS_REST_DISABLE'                    => 'undefined',
			'LLMS_SITE_FEATURE_RECURRING_PAYMENTS' => 'undefined',
			'LLMS_SITE_IS_CLONE'                   => 'undefined',
		);

		foreach ( $data as $constant => &$value ) {

			if ( defined( $constant ) ) {
				$value = constant( $constant ) ? 'true' : 'false';
			}
		}

		return $data;

	}