1 files changed, 62 insertions, 0 deletions
diff --git a/src/js/firstparties/lib/utils.js b/src/js/firstparties/lib/utils.js
new file mode 100644
index 0000000..3edb0c8
--- /dev/null
+++ b/src/js/firstparties/lib/utils.js
@@ -0,0 +1,62 @@
+window.isURL = function(url) {
+  // ensure the URL starts with HTTP or HTTPS; otherwise we might be vulnerable
+  // to XSS attacks
+  return (url && (url.startsWith("https://") || url.startsWith("http://")));
+};
+
+/**
+ * Search a window and all IFrames within it for a query selector, then return a
+ * list of all the elements in any frame that match.
+ */
+window.findInAllFrames = function(query) {
+  let out = [];
+  document.querySelectorAll(query).forEach((node) => {
+    out.push(node);
+  });
+  Array.from(document.getElementsByTagName('iframe')).forEach((iframe) => {
+    try {
+      iframe.contentDocument.querySelectorAll(query).forEach((node) => {
+        out.push(node);
+      });
+    } catch (e) {
+      // pass on cross origin iframe errors
+    }
+  });
+  return out;
+};
+
+/**
+ * Listen for mutations on a page. If any nodes that match `selector` are added
+ * to the page, execute the function `callback` on them.
+ * Used by first-party scripts to listen for new links being added to the page
+ * and strip them of tracking code immediately.
+ */
+window.observeMutations = function(selector, callback) {
+  // Check all new nodes added by a mutation for tracking links and unwrap them
+  function onMutation(mutation) {
+    if (!mutation.addedNodes.length) {
+      return;
+    }
+    for (let node of mutation.addedNodes) {
+      // Only act on element nodes, otherwise querySelectorAll won't work
+      if (node.nodeType != Node.ELEMENT_NODE) {
+        continue;
+      }
+
+      // check all child nodes against the selector first
+      node.querySelectorAll(selector).forEach((element) => {
+        callback(element);
+      });
+
+      // then check the node itself
+      if (node.matches(selector)) {
+        callback(node);
+      }
+    }
+  }
+
+  // Set up a mutation observer with the constructed callback
+  new MutationObserver(function(mutations) {
+    mutations.forEach(onMutation);
+  }).observe(document, {childList: true, subtree: true, attributes: false, characterData: false});
+};