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slab · Jul 29, 2023 · 86af2e9 · 86af2e9
1 parent 93b07d6
commit 86af2e9
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Showing 4 changed files with 130 additions and 94 deletions.
diff --git a/core/quill.ts b/core/quill.ts
@@ -15,6 +15,7 @@ import logger, { DebugLevel } from './logger';
 import Module from './module';
 import Selection, { Range } from './selection';
 import Composition from './composition';
+import { compute } from 'compute-scroll-into-view';
 import Theme, { ThemeConstructor } from './theme';
 
 const debug = logger('quill');
@@ -617,66 +618,29 @@ class Quill {
     const bounds = this.selection.getBounds(range.index, range.length);
     if (bounds == null) return;
 
-    let { top, bottom } = bounds;
-
-    const { body, defaultView } = this.root.ownerDocument;
-    if (!defaultView) return;
-
-    let targetTop = 0;
-    let targetBottom = 0;
-    let targetScaleY = 0;
-    let element: HTMLElement | null = this.root;
-
-    while (element !== null) {
-      const isBodyElement = element === body;
-      if (isBodyElement) {
-        targetTop = 0;
-        targetBottom = defaultView.innerHeight;
-        const targetRect = element.getBoundingClientRect();
-        targetScaleY = targetRect.height / element.offsetHeight;
-      } else {
-        const targetRect = element.getBoundingClientRect();
-        targetTop = targetRect.top;
-        targetBottom = targetRect.bottom;
-        targetScaleY = targetRect.height / element.offsetHeight;
-      }
-      let diff = 0;
-
-      const style = getComputedStyle(element);
-      const borderTop = parseInt(style.borderTopWidth as string, 10);
-      const borderBottom = parseInt(style.borderBottomWidth as string, 10);
-
-      if (top < targetTop) {
-        diff = top - targetTop;
-      } else if (bottom > targetBottom) {
-        const scrollbarHeight =
-          element.offsetHeight -
-          element.clientHeight -
-          borderTop -
-          borderBottom;
-
-        diff =
-          (bottom - targetBottom) / targetScaleY +
-          scrollbarHeight +
-          borderBottom;
-      }
-
-      if (diff) {
-        if (isBodyElement) {
-          defaultView.scrollBy(0, diff);
-        } else {
-          const scrollTop = element.scrollTop;
-          element.scrollTop += diff;
-          const yOffset = (element.scrollTop - scrollTop) * targetScaleY;
-          top -= yOffset;
-          bottom -= yOffset;
-        }
-      }
-      if (isBodyElement) {
-        break;
-      }
-      element = element.parentElement;
-    }
+    // Virtual element is not supported so we have to use a workaround.
+    // https://github.com/scroll-into-view/compute-scroll-into-view
+    const virtualElement = {
+      nodeType: 1,
+      parentElement: this.root,
+      getBoundingClientRect() {
+        return new DOMRect(
+          bounds.left,
+          bounds.top,
+          bounds.width,
+          bounds.height,
+        );
+      },
+    } as unknown as Element;
+
+    compute(virtualElement, {
+      scrollMode: 'if-needed',
+      block: 'nearest',
+      inline: 'nearest',
+    }).forEach(({ el, top, left }) => {
+      el.scrollTop = top;
+      el.scrollLeft = left;
+    });
   }
 
   setContents(

diff --git a/package-lock.json b/package-lock.json
diff --git a/package.json b/package.json
@@ -16,6 +16,7 @@
     "website"
   ],
   "dependencies": {
+    "compute-scroll-into-view": "3.0.3",
     "eventemitter3": "^4.0.7",
     "lodash.clonedeep": "^4.5.0",
     "lodash.isequal": "^4.5.0",

diff --git a/test/unit/core/quill.spec.ts b/test/unit/core/quill.spec.ts
@@ -999,49 +999,109 @@ describe('Quill', () => {
   });
 
   describe('scrollSelectionIntoView', () => {
-    const getAncestorScrollTops = (element: HTMLElement) => {
-      const scrollTops: number[] = [];
-      let current = element.parentElement;
-      while (current) {
-        scrollTops.push(current.scrollTop);
-        current = current.parentElement;
-      }
-      return scrollTops;
+    const viewportRatio = (element: Element): Promise<number> => {
+      return new Promise(resolve => {
+        const observer = new IntersectionObserver(entries => {
+          resolve(entries[0].intersectionRatio);
+          observer.disconnect();
+        });
+        observer.observe(element);
+        // Firefox doesn't call IntersectionObserver callback unless
+        // there are rafs.
+        requestAnimationFrame(() => {});
+      });
     };
 
-    test('scrolls multiple ancestors', () => {
-      document.body.style.height = '500px';
-      const container = document.body.appendChild(
-        document.createElement('div'),
-      );
+    describe('scroll upward', () => {
+      test('scrolls multiple ancestors', async () => {
+        document.body.style.height = '500px';
+        const container = document.body.appendChild(
+          document.createElement('div'),
+        );
 
-      Object.assign(container.style, {
-        height: '100px',
-        overflow: 'scroll',
-      });
+        Object.assign(container.style, {
+          height: '100px',
+          overflow: 'scroll',
+        });
 
-      const space = container.appendChild(document.createElement('div'));
-      space.style.height = '80px';
+        const editorContainer = container.appendChild(
+          document.createElement('div'),
+        );
+        Object.assign(editorContainer.style, {
+          height: '100px',
+          overflow: 'scroll',
+        });
 
-      const editorContainer = container.appendChild(
-        document.createElement('div'),
-      );
-      Object.assign(editorContainer.style, {
-        height: '100px',
-        border: '10px solid red',
-        overflow: 'scroll',
+        const space = container.appendChild(document.createElement('div'));
+        space.style.height = '800px';
+
+        const quill = new Quill(editorContainer);
+
+        let text = '';
+        for (let i = 1; i < 200; i += 1) {
+          text += `line ${i}\n`;
+        }
+        quill.setContents(new Delta().insert(text));
+        quill.setSelection({ index: text.indexOf('line 10'), length: 4 });
+
+        container.scrollTop = -500;
+
+        expect(
+          await viewportRatio(
+            editorContainer.querySelector('p:nth-child(10)') as HTMLElement,
+          ),
+        ).toEqual(1);
+        expect(
+          await viewportRatio(
+            editorContainer.querySelector('p:nth-child(11)') as HTMLElement,
+          ),
+        ).toEqual(0);
       });
+    });
+
+    describe('scroll downward', () => {
+      test('scrolls multiple ancestors', async () => {
+        document.body.style.height = '500px';
+        const container = document.body.appendChild(
+          document.createElement('div'),
+        );
 
-      const quill = new Quill(editorContainer);
+        Object.assign(container.style, {
+          height: '100px',
+          overflow: 'scroll',
+        });
 
-      let text = '';
-      for (let i = 0; i < 200; i += 1) {
-        text += `line ${i}\n`;
-      }
-      quill.setContents(new Delta().insert(text));
-      quill.setSelection({ index: text.indexOf('line 100'), length: 4 });
+        const space = container.appendChild(document.createElement('div'));
+        space.style.height = '80px';
 
-      expect(getAncestorScrollTops(editorContainer)).toEqual([90, 0, 0]);
+        const editorContainer = container.appendChild(
+          document.createElement('div'),
+        );
+        Object.assign(editorContainer.style, {
+          height: '100px',
+          overflow: 'scroll',
+        });
+
+        const quill = new Quill(editorContainer);
+
+        let text = '';
+        for (let i = 1; i < 200; i += 1) {
+          text += `line ${i}\n`;
+        }
+        quill.setContents(new Delta().insert(text));
+        quill.setSelection({ index: text.indexOf('line 100'), length: 4 });
+
+        expect(
+          await viewportRatio(
+            editorContainer.querySelector('p:nth-child(100)') as HTMLElement,
+          ),
+        ).toEqual(1);
+        expect(
+          await viewportRatio(
+            editorContainer.querySelector('p:nth-child(101)') as HTMLElement,
+          ),
+        ).toEqual(0);
+      });
     });
   });
 });