bug: resizable should work within shadow dom

packages/dockview-core/src/__tests__/dom.spec.ts

@@ -1,4 +1,8 @@
-import { quasiDefaultPrevented, quasiPreventDefault } from '../dom';
+import {
+    isInDocument,
+    quasiDefaultPrevented,
+    quasiPreventDefault,
+} from '../dom';
 
 describe('dom', () => {
     test('quasiPreventDefault', () => {
@@ -18,4 +22,27 @@ describe('dom', () => {
         (event as any)['dv-quasiPreventDefault'] = true;
         expect(quasiDefaultPrevented(event)).toBeTruthy();
     });
+
+    test('isInDocument: DOM element', () => {
+        const el = document.createElement('div');
+
+        expect(isInDocument(el)).toBeFalsy();
+
+        document.body.appendChild(el);
+        expect(isInDocument(el)).toBeTruthy();
+    });
+
+    test('isInDocument: Shadow DOM element', () => {
+        const el = document.createElement('div');
+        document.body.appendChild(el);
+
+        const shadow = el.attachShadow({ mode: 'open' });
+
+        const el2 = document.createElement('div');
+        expect(isInDocument(el2)).toBeFalsy();
+
+        shadow.appendChild(el2);
+
+        expect(isInDocument(el2)).toBeTruthy();
+    });
 });

packages/dockview-core/src/dom.ts

@@ -232,3 +232,24 @@ export function getDomNodePagePosition(domNode: Element): {
         height: height,
     };
 }
+
+/**
+ * Check whether an element is in the DOM (including the Shadow DOM)
+ * @see https://terodox.tech/how-to-tell-if-an-element-is-in-the-dom-including-the-shadow-dom/
+ */
+export function isInDocument(element: Element): boolean {
+    let currentElement: Element | ParentNode = element;
+
+    while (currentElement && currentElement.parentNode) {
+        if (currentElement.parentNode === document) {
+            return true;
+        } else if (currentElement.parentNode instanceof DocumentFragment) {
+            // handle shadow DOMs
+            currentElement = (currentElement.parentNode as ShadowRoot).host;
+        } else {
+            currentElement = currentElement.parentNode;
+        }
+    }
+
+    return false;
+}

packages/dockview-core/src/resizable.ts

@@ -1,4 +1,4 @@
-import { watchElementResize } from './dom';
+import { isInDocument, watchElementResize } from './dom';
 import { CompositeDisposable } from './lifecycle';
 
 export abstract class Resizable extends CompositeDisposable {
@@ -45,7 +45,7 @@ export abstract class Resizable extends CompositeDisposable {
                     return;
                 }
 
-                if (!document.body.contains(this._element)) {
+                if (!isInDocument(this._element)) {
                     /**
                      * since the event is dispatched through requestAnimationFrame there is a small chance
                      * the component is no longer attached to the DOM, if that is the case the dimensions