diff --git a/packages-user/data-base/src/map/eventPath.test.ts b/packages-user/data-base/src/map/eventPath.test.ts
index c603772..caeddcb 100644
--- a/packages-user/data-base/src/map/eventPath.test.ts
+++ b/packages-user/data-base/src/map/eventPath.test.ts
@@ -16,6 +16,17 @@ let modules: TestModules;
 
 beforeAll(async () => {
     vi.stubGlobal('main', { replayChecking: true });
+    Map.prototype.getOrInsertComputed ??= function <K, V>(
+        this: Map<K, V>,
+        key: K,
+        callback: (key: K) => V
+    ): V {
+        const existing = this.get(key);
+        if (existing !== undefined) return existing;
+        const value = callback(key);
+        this.set(key, value);
+        return value;
+    };
     const mapModule = await import('./mapState');
     const commonModule = await import('@user/data-common');
     const loggerModule = await import('@motajs/common');
diff --git a/packages-user/data-base/src/map/mapLayer.ts b/packages-user/data-base/src/map/mapLayer.ts
index 129c1ce..59042be 100644
--- a/packages-user/data-base/src/map/mapLayer.ts
+++ b/packages-user/data-base/src/map/mapLayer.ts
@@ -213,20 +213,10 @@ export class MapLayer
     event(x: number, y: number): ILayerEventView | null {
         if (!this.inMap(x, y)) return null;
         const index = y * this.width + x;
-        const getOrInsertComputed = this.pointEvents.getOrInsertComputed;
-        if (getOrInsertComputed) {
-            return getOrInsertComputed.call(
-                this.pointEvents,
-                index,
-                () => new LayerEventView()
-            );
-        }
-        let eventView = this.pointEvents.get(index);
-        if (!eventView) {
-            eventView = new LayerEventView();
-            this.pointEvents.set(index, eventView);
-        }
-        return eventView;
+        return this.pointEvents.getOrInsertComputed(
+            index,
+            () => new LayerEventView()
+        );
     }
 
     getPointEvent(x: number, y: number): ReadonlyMap<number, string> | null {
diff --git a/packages-user/data-base/src/map/mapLifecycle.test.ts b/packages-user/data-base/src/map/mapLifecycle.test.ts
index 12940ef..eb01e9f 100644
--- a/packages-user/data-base/src/map/mapLifecycle.test.ts
+++ b/packages-user/data-base/src/map/mapLifecycle.test.ts
@@ -9,6 +9,17 @@ import {
 vi.hoisted(() => {
     vi.stubGlobal('main', { replayChecking: true });
     vi.stubGlobal('location', { origin: 'http://localhost' });
+    Map.prototype.getOrInsertComputed ??= function <K, V>(
+        this: Map<K, V>,
+        key: K,
+        callback: (key: K) => V
+    ): V {
+        const existing = this.get(key);
+        if (existing !== undefined) return existing;
+        const value = callback(key);
+        this.set(key, value);
+        return value;
+    };
 });
 
 interface TestModules {
diff --git a/packages-user/data-system/src/event/eventDispatch.test.ts b/packages-user/data-system/src/event/eventDispatch.test.ts
index f83bb44..8116e35 100644
--- a/packages-user/data-system/src/event/eventDispatch.test.ts
+++ b/packages-user/data-system/src/event/eventDispatch.test.ts
@@ -18,6 +18,17 @@ import { AnonTokyoInterpreter } from 'anon-tokyo';
 vi.hoisted(() => {
     vi.stubGlobal('main', { replayChecking: true });
     vi.stubGlobal('location', { origin: 'http://localhost' });
+    Map.prototype.getOrInsertComputed ??= function <K, V>(
+        this: Map<K, V>,
+        key: K,
+        callback: (key: K) => V
+    ): V {
+        const existing = this.get(key);
+        if (existing !== undefined) return existing;
+        const value = callback(key);
+        this.set(key, value);
+        return value;
+    };
 });
 
 const eventTriggers = {