fix(menu): respect ion-app dir attribute for menu animation side

core/src/components/menu/menu.tsx

@@ -150,7 +150,7 @@ export class Menu implements ComponentInterface, MenuI {
 
   @Watch('side')
   protected sideChanged() {
-    this.isEndSide = isEnd(this.side);
+    this.isEndSide = isEnd(this.side, this.el);
     /**
      * Menu direction animation is calculated based on the document direction.
      * If the document direction changes, we need to create a new animation.
@@ -499,7 +499,7 @@ export class Menu implements ComponentInterface, MenuI {
      * Menu direction animation is calculated based on the document direction.
      * If the document direction changes, we need to create a new animation.
      */
-    const isEndSide = isEnd(this.side);
+    const isEndSide = isEnd(this.side, this.el);
     if (width === this.width && this.animation !== undefined && isEndSide === this.isEndSide) {
       return;
     }

core/src/components/menu/test/basic/menu.e2e.ts

@@ -137,6 +137,30 @@ configs({ modes: ['md'], directions: ['ltr'] }).forEach(({ title, screenshot, co
       });
       await ionDidClose.next();
     });
+
+    test('should render on the correct side when ion-app direction is rtl', async ({ page }) => {
+      test.info().annotations.push({
+        type: 'issue',
+        description: 'https://github.com/ionic-team/ionic-framework/issues/30226',
+      });
+
+      const ionDidOpen = await page.spyOnEvent('ionDidOpen');
+      const ionDidClose = await page.spyOnEvent('ionDidClose');
+
+      await page.evaluate(() => {
+        document.dir = 'ltr';
+        document.querySelector('ion-app')?.setAttribute('dir', 'rtl');
+      });
+      await page.click('#open-start');
+      await ionDidOpen.next();
+
+      await expect(page).toHaveScreenshot(screenshot(`menu-basic-ion-app-dir-rtl`));
+
+      await page.locator('[menu-id="start-menu"]').evaluate(async (el: HTMLIonMenuElement) => {
+        await el.close();
+      });
+      await ionDidClose.next();
+    });
   });
 });
 

core/src/utils/helpers.spec.ts

@@ -1,4 +1,44 @@
-import { inheritAriaAttributes } from './helpers';
+import { inheritAriaAttributes, isEndSide } from './helpers';
+
+describe('isEndSide', () => {
+  afterEach(() => {
+    document.dir = 'ltr';
+  });
+
+  it('should use document direction when no host element is provided', () => {
+    document.dir = 'rtl';
+    expect(isEndSide('start')).toBe(true);
+    expect(isEndSide('end')).toBe(false);
+  });
+
+  it('should use the nearest ancestor dir attribute', () => {
+    document.dir = 'ltr';
+
+    const app = document.createElement('ion-app');
+    app.setAttribute('dir', 'rtl');
+
+    const menu = document.createElement('ion-menu');
+    app.appendChild(menu);
+    document.body.appendChild(app);
+
+    expect(isEndSide('start', menu)).toBe(true);
+    expect(isEndSide('end', menu)).toBe(false);
+
+    document.body.removeChild(app);
+  });
+
+  it('should fall back to document direction when no ancestor has dir', () => {
+    document.dir = 'rtl';
+
+    const menu = document.createElement('ion-menu');
+    document.body.appendChild(menu);
+
+    expect(isEndSide('start', menu)).toBe(true);
+    expect(isEndSide('end', menu)).toBe(false);
+
+    document.body.removeChild(menu);
+  });
+});
 
 describe('inheritAriaAttributes', () => {
   it('should inherit aria attributes', () => {

core/src/utils/helpers.ts

@@ -1,5 +1,6 @@
 import type { EventEmitter } from '@stencil/core';
 import { printIonError } from '@utils/logging';
+import { isRTL } from '@utils/rtl';
 
 import type { Side } from '../components/menu/menu-interface';
 
@@ -319,15 +320,17 @@ export const pointerCoord = (ev: any): { x: number; y: number } => {
  * Given a side, return if it should be on the end
  * based on the value of dir
  * @param side the side
- * @param isRTL whether the application dir is rtl
+ * @param hostElement the host element used to resolve the nearest ancestor `dir`
  */
-export const isEndSide = (side: Side): boolean => {
-  const isRTL = document.dir === 'rtl';
+export const isEndSide = (side: Side, hostElement?: Element): boolean => {
+  const dirHost = hostElement?.closest('[dir]') as HTMLElement | undefined;
+  const rtl = isRTL(dirHost);
+
   switch (side) {
     case 'start':
-      return isRTL;
+      return rtl;
     case 'end':
-      return !isRTL;
+      return !rtl;
     default:
       throw new Error(`"${side}" is not a valid value for [side]. Use "start" or "end" instead.`);
   }