Sub-domains treated as external URL

Question

I need to add a class external to all the external hyperlink URLS. To achieve this I wrote the javascript

Array.from(document.querySelectorAll('a')).forEach(a => {
    a.classList.add(location.hostname === a.hostname || !a.hostname.length ? 'internal' : 'external');
});

The issue is that the sub-domains are also treated as external and the respective <a> tag is getting external class added. How can I exclude the hyperlinks of sub-domains and also 2 other domains (abc.com and xyz.com) from having the external class added?

Answer 1

而不是location.hostname === a.hostname我会尝试location.hostname.idexOf(a.hostname) >= 0