Imitation of Django’s spaceless tag

spaceless.php

<?php

/**
 * See https://docs.djangoproject.com/en/1.9/ref/templates/builtins/#spaceless
 * Removes whitespace between HTML tags. This includes tab characters and newlines.
 * Only space between tags is removed – not space between tags and text.
 * Single spaces between tags are preserved as they are probably intentional.
 */

function spaceless($string) {
    return preg_replace('/(?!>[ ]<)>\s+</i', '><', $string);
}