From 9fd21b4b81ca20937842f2aa2d1431c4456580a5 Mon Sep 17 00:00:00 2001
From: Alex Alekseyenko <alex@alekseyenko.com>
Date: Sun, 27 Dec 2020 08:36:48 -0800
Subject: [PATCH] Add isContainedWithin function for ShadowRoots

Previously, `el.contains(e)` would return `false` if `e` was inside ShadowRoots. If `el.contains(e)` returns `false`, `isContainedWithin(e, el)` will instead check `e`'s root, and the root's root, and so on, until either `contains` returns `true` or the top of the tree is reached.
---
 content_scripts/utils.js | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/content_scripts/utils.js b/content_scripts/utils.js
index f66dc3dca..ac8de6c26 100644
--- a/content_scripts/utils.js
+++ b/content_scripts/utils.js
@@ -255,6 +255,18 @@ function isExplicitlyRequested(element) {
         element.matches(runtime.conf.clickableSelector);
 }
 
+function isContainedWithin(inner, outer) {
+    // check if outer element contains inner element, recursively
+    // (works even if inner element is inside ShadowRoots)
+    if (!inner) {
+        return false;
+    }
+    if (outer.contains(inner)) {
+        return true;
+    }
+    return isContainedWithin(inner.getRootNode().host, outer);
+}
+
 function filterOverlapElements(elements) {
     // filter out tiny elements
     elements = elements.filter(function(e) {
@@ -265,7 +277,12 @@ function filterOverlapElements(elements) {
             return true;
         } else {
             var el = document.elementFromPoint(be.left + be.width/2, be.top + be.height/2);
-            return !el || el.shadowRoot && el.childElementCount === 0 || el.contains(e) || e.contains(el);
+            return (
+                !el 
+                || el.shadowRoot && el.childElementCount === 0 
+                || isContainedWithin(e, el) 
+                || isContainedWithin(el, e)
+            );
         }
     });