The DOM interface is gated behind dom_xpath_enabled, which is disabled by default.

Links

The DOM XPath spec is kind of a mess, here are some links I dug up:

1. Original, retired spec: https://www.w3.org/TR/DOM-Level-3-XPath/
2. "Living spec": https://dom.spec.whatwg.org/#xpath
3. Some points about what's unspecified from the whatwg wiki: https://wiki.whatwg.org/wiki/DOM_XPath
4. Some points about how XPath in HTML documents works differently: https://html.spec.whatwg.org/multipage/infrastructure.html#interactions-with-xpath-and-xslt

TODO

• XPath: implement lang() and id() core functions #34593
• Invalidating an XPathResult (of the type UNORDERED_NODE_ITERATOR_TYPE or ORDERED_NODE_ITERATOR_TYPE) if the DOM has mutated (Invalidate iterator over elements of a XPathResult when the document changes #39411)
• Allowing an XPathResult to be mutated by a new XPath query evaluation (i.e. evaluate("foo", ..., old_result_to_be_mutated) rather than let new_result = evaluate("foo", ...)
• Better test coverage in general
  • [XPath] Pass all xml_xpath_tests.xml tests #37278

Test coverage

https://github.com/servo/servo/tree/main/tests/wpt/meta/domxpath