Fix memory leak due to focus listeners not being deleted

Author: ysgit

src/Virtual.ts

@@ -257,8 +257,6 @@ export class Virtual {
 
       this.#treeCache =
         this.#container && tree ? flattenTree(this.#container, tree, null) : [];
-
-      this.#attachFocusListeners();
     }
 
     return this.#treeCache;
@@ -290,28 +288,9 @@ export class Virtual {
   }
 
   #invalidateTreeCache() {
-    this.#detachFocusListeners();
     this.#treeCache = null;
   }
 
-  #attachFocusListeners() {
-    this.#getAccessibilityTree().forEach((treeNode) => {
-      treeNode.node.addEventListener(
-        "focus",
-        this.#handleFocusChange.bind(this)
-      );
-    });
-  }
-
-  #detachFocusListeners() {
-    this.#getAccessibilityTree().forEach((treeNode) => {
-      treeNode.node.removeEventListener(
-        "focus",
-        this.#handleFocusChange.bind(this)
-      );
-    });
-  }
-
   async #handleFocusChange({ target }: Event) {
     await tick();
 
@@ -322,10 +301,13 @@ export class Virtual {
       return;
     }
 
-    // We've covered the tree having no length so there must be at least one
-    // index or we default back to the beginning of the tree.
-    const newActiveNode =
-      tree.find(({ node }) => node === target) ?? tree.at(0)!;
+    // We've covered the tree having no length so there should be at least one
+    // matching node, but if not we will not update the state
+    const newActiveNode = tree.find(({ node }) => node === target);
+
+    if (!newActiveNode) {
+      return;
+    }
 
     this.#updateState(newActiveNode, true);
   }
@@ -619,6 +601,8 @@ export class Virtual {
       return;
     }
 
+    this.#container.addEventListener("focusin", this.#handleFocusChange.bind(this));
+
     this.#updateState(tree[0]);
 
     return;