feat(modal): enhance modal behavior and viewport handling for iOS devices

src/app/shared/components/modal-host/modal-host.component.spec.ts

@@ -51,6 +51,10 @@ describe('ModalHostComponent', () => {
   afterEach(() => {
     doc.body.style.overflow = '';
     doc.body.style.paddingRight = '';
+    doc.body.style.position = '';
+    doc.body.style.top = '';
+    doc.body.style.left = '';
+    doc.body.style.width = '';
     TestBed.resetTestingModule();
   });
 
@@ -99,6 +103,10 @@ describe('ModalHostComponent', () => {
     expect(service.activeModal()).toBeNull();
     expect(doc.body.style.overflow).toBe('');
     expect(doc.body.style.paddingRight).toBe('');
+    expect(doc.body.style.position).toBe('');
+    expect(doc.body.style.top).toBe('');
+    expect(doc.body.style.left).toBe('');
+    expect(doc.body.style.width).toBe('');
   });
 
   it('closes on backdrop click when enabled', () => {

src/app/shared/components/modal-host/modal-host.component.ts

@@ -55,11 +55,23 @@ export class ModalHostComponent {
       const body = this.document.body;
       const previousOverflow = body.style.overflow;
       const previousPaddingRight = body.style.paddingRight;
+      const previousPosition = body.style.position;
+      const previousTop = body.style.top;
+      const previousLeft = body.style.left;
+      const previousWidth = body.style.width;
       const view = this.document.defaultView;
+      const scrollX = view?.scrollX ?? 0;
+      const scrollY = view?.scrollY ?? 0;
       const scrollbarWidth = view
         ? Math.max(0, view.innerWidth - this.document.documentElement.clientWidth)
         : 0;
 
+      const activeElement = this.document.activeElement;
+
+      if (activeElement instanceof HTMLElement && activeElement !== body) {
+        activeElement.blur();
+      }
+
       if (scrollbarWidth > 0 && view) {
         const currentPaddingRight =
           Number.parseFloat(view.getComputedStyle(body).paddingRight) || 0;
@@ -68,6 +80,47 @@ export class ModalHostComponent {
 
       body.style.overflow = 'hidden';
 
+      const isIos = view
+        ? /iPad|iPhone|iPod/.test(view.navigator.userAgent) ||
+          (view.navigator.platform === 'MacIntel' && view.navigator.maxTouchPoints > 1)
+        : false;
+
+      if (isIos) {
+        body.style.position = 'fixed';
+        body.style.top = `${-scrollY}px`;
+        body.style.left = `${-scrollX}px`;
+        body.style.width = '100%';
+      }
+
+      let viewportFrame: number | undefined;
+      const viewportSyncTimers: number[] = [];
+      const syncVisualViewport = () => {
+        if (!view) {
+          return;
+        }
+
+        if (viewportFrame !== undefined) {
+          view.cancelAnimationFrame(viewportFrame);
+        }
+
+        viewportFrame = view.requestAnimationFrame(() => {
+          viewportFrame = undefined;
+          this.modalShell()?.setVisualViewport(view.visualViewport, view.scrollX, view.scrollY);
+        });
+      };
+
+      view?.visualViewport?.addEventListener('resize', syncVisualViewport);
+      view?.visualViewport?.addEventListener('scroll', syncVisualViewport);
+      view?.addEventListener('orientationchange', syncVisualViewport);
+      syncVisualViewport();
+
+      if (view) {
+        viewportSyncTimers.push(
+          view.setTimeout(syncVisualViewport, 100),
+          view.setTimeout(syncVisualViewport, 300),
+        );
+      }
+
       const onKeyDown = (event: KeyboardEvent) => {
         if (event.key !== 'Escape' || !this.activeModal()?.config.closeOnEscape) {
           return;
@@ -82,8 +135,26 @@ export class ModalHostComponent {
 
       onCleanup(() => {
         this.document.removeEventListener('keydown', onKeyDown);
+        view?.visualViewport?.removeEventListener('resize', syncVisualViewport);
+        view?.visualViewport?.removeEventListener('scroll', syncVisualViewport);
+        view?.removeEventListener('orientationchange', syncVisualViewport);
+
+        if (viewportFrame !== undefined) {
+          view?.cancelAnimationFrame(viewportFrame);
+        }
+
+        viewportSyncTimers.forEach((timer) => view?.clearTimeout(timer));
+
         body.style.overflow = previousOverflow;
         body.style.paddingRight = previousPaddingRight;
+        body.style.position = previousPosition;
+        body.style.top = previousTop;
+        body.style.left = previousLeft;
+        body.style.width = previousWidth;
+
+        if (isIos) {
+          view?.scrollTo(scrollX, scrollY);
+        }
       });
     });
   }