Need a bi-directional API for utilizing both node & virtualNode

[marcysutton]

In doing the work for #690, I found some checks still use accessibleText instead of accessibleTextVirtual, probably because they're using DOM APIs and filtering on DOM nodes. This makes it difficult to call accessibleTextVirtual without having to redo the work in accessibleText (and sort-of negates the point of doing it).

We talked about creating a bi-directional API so you can move more easily between node and virtualNode–that's what this issue is about. Can we add a virtualNode property to DOM nodes, or are those readonly?

Here's an example from lib/checks/label/explicit.js:

if (node.getAttribute('id')) {
	const root = axe.commons.dom.getRootNode(node);
	const id = axe.commons.utils.escapeSelector(node.getAttribute('id'));
	const label = root.querySelector(`label[for="${id}"]`);

	if (label) {
		return !!axe.commons.text.accessibleText(label);
	}
}
return false;

Because the label element is found by querying the DOM from an explicit ID on the node under test, you can't use accessibleTextVirtual here without getNodeFromTree. Other examples of checks that have this problem include:

accessibleText

• lib/checks/forms/fieldset.js
• lib/checks/forms/labelledby.js
• lib/checks/label/help-same-as-label.js
• lib/checks/shared/aria-labelledby.js
• lib/checks/tables/headers-visible-text.js
• lib/checks/tables/same-caption-summary.js

hasContent

• lib/checks/navigation/region.js
• lib/checks/tables/td-has-header.js
• lib/checks/tables/th-has-data-cells.js

[dylanb]

@marcysutton we do have a bi-directional API - we have getNodeFromTree and actualNode

The issue here is more complicated. IDREFS are only valid within the scope of a single root. The code example you list is taking advantage of this by using Element.querySelector instead of axe.utils,querySelectorAll.

We could "fix" the code by using axe.utils.querySelectorAll instead but would have to ensure we have tests to ensure that selectors with [for=X] stay within the scope of the current root.

[WilcoFiers]

I'm taking off the tag. We're not going to get this done before 3.0.