Check whether a page contains a given body class.

has_body_class.php

<?php
/**
 * Conditional to check whether or not the body class contains a given class.
 *
 * @param  string $class The class we're lookging for in the body class.
 */
function has_body_class( $class ) {

	$body_classes = get_body_class();
	return in_array( $class, $body_classes, true );

}

Thank you for sharing this. It's exactly what I needed.