Issue title: How to get domain from URL ？
 Issue body: function({ url, oldValue }) { return location.hostname; }
it doesn't work 
 Comments: 
 Comment 0: You will need to parse the url to get the hostname
{'source': 'GithubIssues', 'repo_name_with_owner': 'bewisse/modheader', 'issue_id': 1077154632, 'repo_stars': 237.0}