From 1cf4741b2be708289bf73518443d2b2a41517d00 Mon Sep 17 00:00:00 2001
From: mmuehlich <32823494+mmuehlich@users.noreply.github.com>
Date: Fri, 18 Apr 2025 09:36:04 +0000
Subject: [PATCH] Set composed and composedPath() for Events within shadow DOM

---
 ts/drag-drop-touch-util.ts | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/ts/drag-drop-touch-util.ts b/ts/drag-drop-touch-util.ts
index 0f1457f..d9ad5ae 100644
--- a/ts/drag-drop-touch-util.ts
+++ b/ts/drag-drop-touch-util.ts
@@ -59,6 +59,7 @@ export function newForwardableEvent(
   const evt = new Event(type, {
       bubbles: true,
       cancelable: true,
+      composed: target.shadowRoot?.mode === "open",
     }) as unknown as Mutable<MouseEvent, "button" | "which" | "buttons"> & {
       readonly defaultPrevented: boolean;
     },
@@ -68,6 +69,19 @@ export function newForwardableEvent(
   copyProps(evt, srcEvent, _kbdProps);
   copyProps(evt, touch, _ptProps);
   setOffsetAndLayerProps(evt, target);
+  // set composedPath for shadow DOM
+  if (evt.composed) {
+    evt.composedPath = () => {
+      const pt = pointFrom(srcEvent);
+      const el = target.shadowRoot?.elementFromPoint(pt.x, pt.y);
+      const getPath = (e?: Element | null, path: Element[] = []) => {
+        if (!e) return path;
+        path.unshift(e);
+        return getPath(e.parentElement, path);
+      };
+      return getPath(el);
+    };
+  }
   return evt;
 }