Issue 6848 - Add searchSelector parameter to hide-if-contains snippet

lib/content/snippets.js

Index: lib/content/snippets.js
===================================================================
--- a/lib/content/snippets.js
+++ b/lib/content/snippets.js
@@ -92,17 +92,17 @@
  */
 function makeInjector(injectable, ...dependencies)
 {
   return (...args) => injectCode(stringifyFunctionCall(injectable, ...args),
                                  dependencies);
 }
 
 /**
- * Hides an HTML element by settings its <code>style</code> attribute to
+ * Hides an HTML element by setting its <code>style</code> attribute to
  * <code>display: none !important</code>.
  *
  * @param {HTMLElement} element The HTML element to hide.
  */
 function hideElement(element)
 {
   element.style.setProperty("display", "none", "important");
 
@@ -212,27 +212,19 @@
     if (!host || !root)
       return;
 
     // If the shadow contains the given text, check if the host or one of its
     // ancestors matches the selector; if a matching element is found, hide
     // it.
     if (root.textContent.includes(search))
     {
-      let element = host;
-
-      do
-      {
-        if (element.matches(selector))
-        {
-          hideElement(element);
-          break;
-        }
-      }
-      while (element = element.parentElement);
+      let closest = host.closest(selector);
+      if (closest)
+        hideElement(closest);
     }
   }
 
   Object.defineProperty(Element.prototype, "attachShadow", {
     value(...args)
     {
       // Create the shadow root first. It doesn't matter if it's a closed
       // shadow root, we keep the reference in a weak map.
@@ -256,31 +248,41 @@
     }
   });
 }
 
 exports["hide-if-shadow-contains"] = makeInjector(hideIfShadowContains,
                                                   hideElement);
 
 /**
- * Hides any HTML element if the text content of the element contains a given
- * string.
+ * Hides any HTML element or one of its ancestors matching a CSS selector if
+ * the text content of the element contains a given string.
  *
- * @param {string} search The string to look for in every HTML element.
+ * @param {string} search The string to look for in HTML elements.
  * @param {string} selector The CSS selector that an HTML element must match
  *   for it to be hidden.
+ * @param {string?} [searchSelector] The CSS selector that an HTML element
+ *   containing the given string must match. Defaults to the value of the
+ *   <code>selector</code> argument.
  */
-function hideIfContains(search, selector = "*")
+function hideIfContains(search, selector = "*", searchSelector = null)
 {
+  if (searchSelector == null)
+    searchSelector = selector;
+
   new MutationObserver(() =>
   {
-    for (let element of document.querySelectorAll(selector))
+    for (let element of document.querySelectorAll(searchSelector))
     {
       if (element.textContent.includes(search))
-        hideElement(element);
+      {
+        let closest = element.closest(selector);
+        if (closest)
+          hideElement(closest);
+      }
     }
   })
   .observe(document, {childList: true, characterData: true, subtree: true});
 }
 
 exports["hide-if-contains"] = hideIfContains;
 
 /**