localhost / userdir on macOS High Sierra
Like on Sierra vhosts seem to need to be activated
so:
sudo vi /etc/apache2/httpd.conf
and uncomment the following lines by removing the hashtag (#)
.#LoadModule vhost_alias_module libexec/apache2/mod_vhost_alias.so
and
.#Include /private/etc/apache2/extra/httpd-vhosts.conf
then
sudo apachectl restart
and you'll be good to go