Problem: Implement a Custom querySelectorAll for a Hidden URL

A webpage conceals a URL by distributing its individual characters across deeply nested DOM elements. Your task is to implement a simplified selector engine, similar to querySelectorAll, but without using the browser's built-in querySelector or querySelectorAll methods.

This custom engine will then be used to locate the hidden character elements and reconstruct the URL.

DOM Snippet Example

<section data-id="23*">
  <article data-class="*45">
    <div data-tag="*78*">
      <b class="ref" value="h"></b>
      <b class="ref" value="t"></b>
      <b class="ref" value="t"></b>
      <b class="ref" value="p"></b>
      <!-- ...more <b> nodes each holding one character... -->
    </div>
  </article>
</section>

Selector Syntax to Support

You must implement the function signature:

function querySelectorAll(root, selector) { /* ... */ }

Where selector is a descendant chain separated by spaces. For example:

section[data-id="23*"] article[data-class="*45"] div[data-tag="*78*"] b.ref

Each segment in the selector chain may contain:

• A tag name (e.g., section, div, b)
• At most one class (e.g., .ref)
• At most one attribute filter like [data-id="PATTERN"]

Attribute filter patterns may include * wildcards:

• * matches any string (including empty).
• Examples:
  • "23*" matches "23", "230", "23abc"
  • "*45" matches "45", "abc45"
  • "*78*" matches "78", "a78b", "xx78"

Task

1. Implement querySelectorAll(root, selector) to return all matching elements in document order.
2. Use your implemented function to find all matching <b class="ref"> nodes.
3. Reconstruct the hidden URL by concatenating the value attribute of each found <b> node in their document order.

Output

Return the reconstructed URL as a string.

Constraints / Assumptions

• The DOM is a tree of elements with tagName, getAttribute(name), classList, and children (or equivalent properties).
• No commas, > , + , :nth-child , or other complex CSS features are supported—only the subset described above.
• The hidden URL characters appear in the correct order in the DOM traversal order under the matched container.