Issue 7450 - Implement hide-if-contains-visible-text snippet

lib/content/snippets.js

Index: lib/content/snippets.js
===================================================================
--- a/lib/content/snippets.js
+++ b/lib/content/snippets.js
@@ -403,50 +403,149 @@
 }
 
 exports["hide-if-shadow-contains"] = makeInjector(hideIfShadowContains,
                                                   toRegExp, regexEscape,
                                                   hideElement);
 
 /**
  * Hides any HTML element or one of its ancestors matching a CSS selector if
+ * it matches the provided condition.
+ *
+ * @param {function} match The function that provides the matching condition.
+ * @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

[Manish Jethani, 2019/04/17 18:52:35]

Nit: Maybe a good opportunity to fix the JSDoc: `?string` instead of `string?`

[hub, 2019/04/17 21:38:06]

Done.

+ *   containing the given string must match. Defaults to the value of the
+ *   <code>selector</code> argument.
+ */
+function hideIfMatch(match, selector, searchSelector)

[Manish Jethani, 2019/04/17 18:52:34]

Nit: Suggestion: `hideIfMatches()`

[hub, 2019/04/17 21:38:06]

Done.

+{
+  if (searchSelector == null)
+    searchSelector = selector;
+
+  new MutationObserver(() =>
+  {
+    for (let element of document.querySelectorAll(searchSelector))
+    {
+      if (match(element))
+      {
+        let closest = element.closest(selector);
+        if (closest)
+          hideElement(closest);
+      }
+    }
+  })
+  .observe(document, {childList: true, characterData: true, subtree: true});
+}
+
+/**
+ * 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 HTML elements. If the
  *   string begins and ends with a slash (<code>/</code>), the text in between
  *   is treated as a regular expression.
  * @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 = "*", searchSelector = null)
 {
-  if (searchSelector == null)
-    searchSelector = selector;
+  let re = toRegExp(search);
+
+  hideIfMatch(element => re.test(element.textContent),
+              selector, searchSelector);
+}
+
+exports["hide-if-contains"] = hideIfContains;
+
+/**
+ * Hides any HTML element matching a CSS selector if the visible text content
+ * of the element contains a given string.
+ *
+ * @param {string} search The text to match to the visible text. Is considered

[Manish Jethani, 2019/04/17 18:52:35]

Nit: s/The text to match/The string to match/

Nit: s/Is considered visible text that isn't/Text is considered visible if it
isn't/

[hub, 2019/04/17 21:38:06]

Done.

+ *   visible text that isn't hidden by CSS properties or other means.
+ *   If the string begins and ends with a slash (<code>/</code>), the
+ *   text in between is treated as a regular expression.
+ * @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 hideIfContainsVisibleText(search, selector, searchSelector = null)
+{
+  /**
+   * Determines if the text inside the element is visible.
+   * @param {Element} element The leaf element we are checking.

[Manish Jethani, 2019/04/17 18:52:35]

Nit: Shouldn't this just be "The element", since whether it's a leaf or not is
not relevant to this function?

[hub, 2019/04/17 21:38:06]

Done.

+   * @param {?CSSStyleDeclaration} [style] The computed style of element. If
+   *   falsey it will be queried.
+   * @returns {bool} Whether the text is visible.
+   */
+  function isTextVisible(element, style)
+  {
+    if (!style)
+      style = window.getComputedStyle(element);

[Manish Jethani, 2019/04/17 18:52:34]

Nit: `window.` is kinda redundant here, but maybe it also makes things clearer.
Up to you.

[hub, 2019/04/17 21:38:06]

Acknowledged.

+
+    if (style.getPropertyValue("opacity") == "0")
+      return false;
+    if (style.getPropertyValue("font-size") == "0px")
+      return false;
+    if (style.getPropertyValue("color") ==
+        style.getPropertyValue("background-color"))
+      return false;
+
+    return true;
+  }
+
+  /**
+   * Returns the visible text content from an element and its children.

[Manish Jethani, 2019/04/17 18:52:35]

Nit: "and its children" is kinda redundant, but if we want to be specific then
"and its descendants" would be more accurate since it's recursive.

[hub, 2019/04/17 21:38:06]

Done.

+   * @param {Element} element The element whose visible text we want.
+   * @returns {string} The text that is visible.
+   */
+  function getVisibleContent(element)
+  {
+    let style = window.getComputedStyle(element);
+    if (style.getPropertyValue("display") == "none")
+      return "";
+    let visibility = style.getPropertyValue("visibility");
+    if (visibility == "hidden" || visibility == "collapse")
+      return "";
+
+    let text = "";
+    for (let node of element.childNodes)
+    {
+      switch (node.nodeType)
+      {
+        case Node.ELEMENT_NODE:
+          text += getVisibleContent(node);
+          break;
+        case Node.TEXT_NODE:
+          if (isTextVisible(element, style))
+            text += node.nodeValue;
+          break;
+      }
+    }
+    return text;
+  }
 
   let re = toRegExp(search);
 
-  new MutationObserver(() =>
+  hideIfMatch(element =>

[Manish Jethani, 2019/04/17 18:52:35]

Wondering if we can shorten this to:

  hideIfMatch(element => getVisibleContent(element).test(content),
              selector, searchSelector);

[hub, 2019/04/17 21:38:06]

No exactly. But ok.

[Manish Jethani, 2019/04/18 08:40:43]

Ah, sorry I got that wrong.

Thanks.

   {
-    for (let element of document.querySelectorAll(searchSelector))
-    {
-      if (re.test(element.textContent))
-      {
-        let closest = element.closest(selector);
-        if (closest)
-          hideElement(closest);
-      }
-    }
-  })
-  .observe(document, {childList: true, characterData: true, subtree: true});
+    let content = getVisibleContent(element);
+    return re.test(content);
+  }, selector, searchSelector);
 }
 
-exports["hide-if-contains"] = hideIfContains;
+exports["hide-if-contains-visible-text"] =
+  makeInjector(hideIfContainsVisibleText, hideIfMatch, hideElement);

[hub, 2019/04/17 17:27:02]

It doesn't need to be a type 2. I need to fix the testing code to allow testing
type 1.

 
 /**
  * Hides any HTML element or one of its ancestors matching a CSS selector if
  * the text content of the element contains a given string and, optionally, if
  * the element's computed style contains a given string.
  *
  * @param {string} search The string to look for in HTML elements. If the
  *   string begins and ends with a slash (<code>/</code>), the text in between