What?

Fixes a bug where HTML comments appear at the end of an element (that is, they don't have a next sibling). E.g.:

<ul data-wp-interactive="example">
  <li>Item 1</li>
  <li>Item 2</li>
  <!-- End of list  (HTML comment without a next sibling) -->
</ul>

The toVdom() function was wrongly expecting a sibling after processed comments. The same thing happens for processing instructions and CDATA blocks since they are processed in the same way as comments.

Props to @luisherranz.

Why?

This case passed under the radar.

How?

The toVdom() function now waits until the end of the current element processing to delete the comments (also delete the processing instructions and transform CDATA blocks into text). This prevents execution failure once the function reaches treeWalker.parentNode() and the parent doesn't exist (because the current node has been deleted or replaced).

Additionally, it is no longer necessary for toVdom (and internally walk) to return an array. This has been conveniently updated.

Tests

The previous e2e tests have been updated, and a comprehensive unit test suite for toVdom() has been implemented.