How to get "raw" href contents in JavaScript

Try the getAttribute method instead.

Typical. I figured it out myself almost immediately after posting the question.

instead of:

anchor.href

use:

anchor.getAttribute("href")

Of course, it took me longer to type in this answer than it took everyone else to answer it. (Damn, you people are fast.)

Here's a code snippet you could run to test.

const anchors = document.getElementsByTagName('a');

for (let anchor of anchors) {
  let hrefFullPath = anchor.href;
  let hrefRelativePath = anchor.attributes.href.value;

  console.log('hrefFullPath', hrefFullPath);
  console.log('hrefRelativePath', hrefRelativePath);
}

Let's say, you are at http://localhost:4200, and this is your document as you have shown in the question.

<a id="rel" href="/relative/link">inner</a>

This anchor's attribute value of href is:

document.getElementById('rel').attributes.href.value => /relative/link

And anchor's href value is:

document.getElementById('rel').href =>  http://localhost:4200/relative/link

I hope it helps.