fix(modal): allow pull-to-refresh with a custom scroll host

core/src/components/modal/gestures/sheet.ts

@@ -7,7 +7,7 @@ import type { Animation, ModalDragEventDetail } from '../../../interface';
 import type { GestureDetail } from '../../../utils/gesture';
 import { getBackdropValueForSheet } from '../utils';
 
-import { calculateSpringStep, handleCanDismiss } from './utils';
+import { calculateSpringStep, canSwipeOnContent, handleCanDismiss } from './utils';
 
 export interface MoveSheetToBreakpointOptions {
   /**
@@ -261,9 +261,6 @@ export const createSheetGesture = (
 
   const canStart = (detail: GestureDetail) => {
     /**
-     * If we are swiping on the content, swiping should only be possible if the content
-     * is scrolled all the way to the top so that we do not interfere with scrolling.
-     *
      * We cannot assume that the `ion-content` target will remain consistent between swipes.
      * For example, when using ion-nav within a modal it is possible to swipe, push a view,
      * and then swipe again. The target content will not be the same between swipes.
@@ -272,27 +269,11 @@ export const createSheetGesture = (
     currentBreakpoint = getCurrentBreakpoint();
 
     /**
-     * If `expandToScroll` is disabled, we should not allow the swipe gesture
-     * to start if the content is not scrolled to the top.
+     * Upwards swipes on the content cannot move the sheet anyway, so this only
+     * blocks swiping the sheet down from the content.
      */
-    if (!expandToScroll && contentEl) {
-      const scrollEl = isIonContent(contentEl) ? getElementRoot(contentEl).querySelector('.inner-scroll') : contentEl;
-      return scrollEl!.scrollTop === 0;
-    }
-
-    if (currentBreakpoint === 1 && contentEl) {
-      /**
-       * The modal should never swipe to close on the content with a refresher.
-       * Note 1: We cannot solve this by making this gesture have a higher priority than
-       * the refresher gesture as the iOS native refresh gesture uses a scroll listener in
-       * addition to a gesture.
-       *
-       * Note 2: Do not use getScrollElement here because we need this to be a synchronous
-       * operation, and getScrollElement is asynchronous.
-       */
-      const scrollEl = isIonContent(contentEl) ? getElementRoot(contentEl).querySelector('.inner-scroll') : contentEl;
-      const hasRefresherInContent = !!contentEl.querySelector('ion-refresher');
-      return !hasRefresherInContent && scrollEl!.scrollTop === 0;
+    if (contentEl && (!expandToScroll || currentBreakpoint === 1)) {
+      return canSwipeOnContent(contentEl);
     }
 
     return true;

core/src/components/modal/gestures/swipe-to-close.ts

@@ -1,15 +1,15 @@
 import { getTimeGivenProgression } from '@utils/animation/cubic-bezier';
 import { isIonContent, findClosestIonContent, disableContentScrollY, resetContentScrollY } from '@utils/content';
 import { createGesture } from '@utils/gesture';
-import { clamp, getElementRoot } from '@utils/helpers';
+import { clamp } from '@utils/helpers';
 import { OVERLAY_GESTURE_PRIORITY } from '@utils/overlays';
 
 import type { Animation, ModalDragEventDetail } from '../../../interface';
 import type { GestureDetail } from '../../../utils/gesture';
 import type { Style as StatusBarStyle } from '../../../utils/native/status-bar';
 import { setCardStatusBarDark, setCardStatusBarDefault } from '../utils';
 
-import { calculateSpringStep, handleCanDismiss } from './utils';
+import { calculateSpringStep, canSwipeOnContent, handleCanDismiss } from './utils';
 
 // Defaults for the card swipe animation
 export const SwipeToCloseDefaults = {
@@ -35,7 +35,6 @@ export const createSwipeToCloseGesture = (
   let isOpen = false;
   let canDismissBlocksGesture = false;
   let contentEl: HTMLElement | null = null;
-  let scrollEl: HTMLElement | null = null;
   const canDismissMaxStep = 0.2;
   let initialScrollY = true;
   let lastStep = 0;
@@ -60,12 +59,6 @@ export const createSwipeToCloseGesture = (
     }
 
     /**
-     * If we are swiping on the content,
-     * swiping should only be possible if
-     * the content is scrolled all the way
-     * to the top so that we do not interfere
-     * with scrolling.
-     *
      * We cannot assume that the `ion-content`
      * target will remain consistent between
      * swipes. For example, when using
@@ -76,29 +69,7 @@ export const createSwipeToCloseGesture = (
      */
     contentEl = findClosestIonContent(target);
     if (contentEl) {
-      /**
-       * The card should never swipe to close
-       * on the content with a refresher.
-       * Note: We cannot solve this by making the
-       * swipeToClose gesture have a higher priority
-       * than the refresher gesture as the iOS native
-       * refresh gesture uses a scroll listener in
-       * addition to a gesture.
-       *
-       * Note: Do not use getScrollElement here
-       * because we need this to be a synchronous
-       * operation, and getScrollElement is
-       * asynchronous.
-       */
-      if (isIonContent(contentEl)) {
-        const root = getElementRoot(contentEl);
-        scrollEl = root.querySelector('.inner-scroll');
-      } else {
-        scrollEl = contentEl;
-      }
-
-      const hasRefresherInContent = !!contentEl.querySelector('ion-refresher');
-      return !hasRefresherInContent && scrollEl!.scrollTop === 0;
+      return canSwipeOnContent(contentEl);
     }
 
     /**

core/src/components/modal/gestures/utils.ts

@@ -1,7 +1,26 @@
+import { findRefresherInContent, isIonContent } from '@utils/content';
+import { getElementRoot } from '@utils/helpers';
 import { GESTURE } from '@utils/overlays';
 
 import type { Animation } from '../../../interface';
 
+/**
+ * Swiping is only possible when the content is scrolled to the top, so that we
+ * do not interfere with scrolling, and never on content with a refresher.
+ *
+ * Note: We cannot solve the refresher case with gesture priority as the iOS
+ * native refresh gesture uses a scroll listener in addition to a gesture.
+ *
+ * Note: Do not use `getScrollElement` here because we need this to be a
+ * synchronous operation, and `getScrollElement` is asynchronous.
+ */
+export const canSwipeOnContent = (contentEl: HTMLElement) => {
+  const scrollEl = isIonContent(contentEl) ? getElementRoot(contentEl).querySelector('.inner-scroll') : contentEl;
+  const hasRefresherInContent = !!findRefresherInContent(contentEl);
+
+  return !hasRefresherInContent && scrollEl!.scrollTop === 0;
+};
+
 export const handleCanDismiss = async (el: HTMLIonModalElement, animation: Animation) => {
   /**
    * If canDismiss is not a function

core/src/components/modal/test/refresher-scroll-target/index.html

@@ -0,0 +1,136 @@
+<!DOCTYPE html>
+<html lang="en" dir="ltr">
+  <head>
+    <meta charset="UTF-8" />
+    <title>Modal - Refresher with Custom Scroll Target</title>
+    <meta name="apple-mobile-web-app-capable" content="yes" />
+    <meta name="apple-mobile-web-app-status-bar-style" content="black-translucent" />
+    <meta
+      name="viewport"
+      content="viewport-fit=cover, width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=no"
+    />
+    <link href="../../../../../../css/ionic.bundle.css" rel="stylesheet" />
+    <link href="../../../../../../scripts/testing/styles.css" rel="stylesheet" />
+    <script src="../../../../../../scripts/testing/scripts.js"></script>
+    <script type="module" src="../../../../../../dist/ionic/ionic.esm.js"></script>
+
+    <style>
+      #content {
+        position: relative;
+
+        display: block;
+        flex: 1;
+
+        height: 100%;
+        overflow-y: auto;
+
+        contain: size style;
+      }
+    </style>
+  </head>
+
+  <script type="module">
+    import { modalController } from '../../../../../dist/ionic/index.esm.js';
+    window.modalController = modalController;
+  </script>
+
+  <body>
+    <ion-app>
+      <div class="ion-page">
+        <ion-header>
+          <ion-toolbar>
+            <ion-title>Refresher with Custom Scroll Target</ion-title>
+          </ion-toolbar>
+        </ion-header>
+
+        <ion-content class="ion-padding">
+          <button class="expand" id="card" onclick="presentCardModal()">Card Modal</button>
+          <button class="expand" id="sheet" onclick="presentSheetModal()">Sheet Modal</button>
+          <button class="expand" id="sheet-no-expand" onclick="presentSheetModal({ expandToScroll: false })">
+            Sheet Modal (expandToScroll false)
+          </button>
+          <button class="expand" id="sheet-breakpoints" onclick="presentSheetModal(MULTIPLE_BREAKPOINTS)">
+            Sheet Modal (breakpoints)
+          </button>
+          <button
+            class="expand"
+            id="sheet-breakpoints-no-expand"
+            onclick="presentSheetModal({ ...MULTIPLE_BREAKPOINTS, expandToScroll: false })"
+          >
+            Sheet Modal (breakpoints, expandToScroll false)
+          </button>
+        </ion-content>
+      </div>
+    </ion-app>
+
+    <script>
+      const MULTIPLE_BREAKPOINTS = { breakpoints: [0, 0.25, 0.5, 1], initialBreakpoint: 0.5 };
+
+      // The refresher is a child of ion-content while the scroll host is a
+      // sibling of it, matching how virtual scroll viewports are set up.
+      function createModalContent() {
+        const element = document.createElement('div');
+        element.innerHTML = `
+      <ion-header id="modal-header">
+        <ion-toolbar>
+          <ion-title>Modal</ion-title>
+        </ion-toolbar>
+      </ion-header>
+      <ion-content scroll-y="false">
+        <ion-refresher id="refresher" slot="fixed">
+          <ion-refresher-content pulling-text="Pull to refresh" refreshing-text="Refreshing..."></ion-refresher-content>
+        </ion-refresher>
+        <div id="content" class="ion-padding ion-content-scroll-host">
+          <ion-list id="list"></ion-list>
+        </div>
+      </ion-content>
+      `;
+
+        const list = element.querySelector('#list');
+        for (let i = 0; i < 30; i++) {
+          const item = document.createElement('ion-item');
+          item.textContent = `Item ${i}`;
+          list.appendChild(item);
+        }
+
+        let refreshCount = 0;
+        const refresher = element.querySelector('#refresher');
+        refresher.addEventListener('ionRefresh', () => {
+          // Hold the refreshing state so the spinner is visible when testing by
+          // hand, then prepend an item so the refresh leaves something behind.
+          setTimeout(() => {
+            refreshCount++;
+
+            const item = document.createElement('ion-item');
+            item.setAttribute('color', 'success');
+            item.textContent = `Refreshed ${refreshCount}`;
+            list.prepend(item);
+
+            refresher.complete();
+          }, 1500);
+        });
+
+        return element;
+      }
+
+      async function presentCardModal() {
+        const modal = await modalController.create({
+          // ion-app also carries the ion-page class, so the page is the second match.
+          presentingElement: document.querySelectorAll('.ion-page')[1],
+          component: createModalContent(),
+        });
+        await modal.present();
+      }
+
+      async function presentSheetModal(opts = {}) {
+        const modal = await modalController.create({
+          component: createModalContent(),
+          breakpoints: [0, 1],
+          initialBreakpoint: 1,
+          ...opts,
+        });
+        await modal.present();
+      }
+    </script>
+  </body>
+</html>