From d8a8b900ab2e17e6e81e25746ffba1aea757dc34 Mon Sep 17 00:00:00 2001
From: zombiej <smith3816@gmail.com>
Date: Tue, 25 Aug 2020 14:49:25 +0800
Subject: [PATCH 1/2] fix: Add patch fix for firefox mouse wheel

---
 src/List.tsx               | 18 +++++++++--------
 src/hooks/useFrameWheel.ts | 40 +++++++++++++++++++++++++++++++++-----
 src/utils/isFirefox.ts     |  2 ++
 3 files changed, 47 insertions(+), 13 deletions(-)
 create mode 100644 src/utils/isFirefox.ts

diff --git a/src/List.tsx b/src/List.tsx
index 0dbd6f1a..a6aede77 100644
--- a/src/List.tsx
+++ b/src/List.tsx
@@ -188,14 +188,6 @@ export function RawList<T>(props: ListProps<T>, ref: React.Ref<ListRef>) {
   const keepInRange = useInRange(scrollHeight, height);
 
   // ================================ Scroll ================================
-  // Since this added in global,should use ref to keep update
-  const onRawWheel = useFrameWheel(inVirtual, offsetY => {
-    syncScrollTop(top => {
-      const newTop = keepInRange(top + offsetY);
-      return newTop;
-    });
-  });
-
   function onScrollBar(newScrollTop: number) {
     const newTop = keepInRange(newScrollTop);
     if (newTop !== scrollTop) {
@@ -215,10 +207,20 @@ export function RawList<T>(props: ListProps<T>, ref: React.Ref<ListRef>) {
     onScroll?.(e);
   }
 
+  // Since this added in global,should use ref to keep update
+  const [onRawWheel, onFireFoxScroll] = useFrameWheel(inVirtual, offsetY => {
+    syncScrollTop(top => {
+      const newTop = keepInRange(top + offsetY);
+      return newTop;
+    });
+  });
+
   React.useEffect(() => {
     componentRef.current.addEventListener('wheel', onRawWheel);
+    componentRef.current.addEventListener('DOMMouseScroll', onFireFoxScroll as any);
     return () => {
       componentRef.current.removeEventListener('wheel', onRawWheel);
+      componentRef.current.removeEventListener('DOMMouseScroll', onFireFoxScroll as any);
     };
   }, [inVirtual]);
 
diff --git a/src/hooks/useFrameWheel.ts b/src/hooks/useFrameWheel.ts
index 110c112a..53d41639 100644
--- a/src/hooks/useFrameWheel.ts
+++ b/src/hooks/useFrameWheel.ts
@@ -1,24 +1,54 @@
 import { useRef } from 'react';
 import raf from 'rc-util/lib/raf';
+import isFF from '../utils/isFirefox';
 
-export default function useFrameWheel(inVirtual: boolean, onWheelDelta: (offset: number) => void) {
+interface FireFoxDOMMouseScrollEvent {
+  detail: number;
+  preventDefault: Function;
+}
+
+export default function useFrameWheel(
+  inVirtual: boolean,
+  onWheelDelta: (offset: number) => void,
+): [(e: WheelEvent) => void, (e: FireFoxDOMMouseScrollEvent) => void] {
   const offsetRef = useRef(0);
   const nextFrameRef = useRef<number>(null);
 
-  function onWheel(event: MouseWheelEvent) {
+  // Firefox patch
+  const wheelValueRef = useRef<number>(null);
+  const isMouseScrollRef = useRef<boolean>(false);
+
+  function onWheel(event: WheelEvent) {
     if (!inVirtual) return;
 
     // Proxy of scroll events
-    event.preventDefault();
+    if (!isFF) {
+      event.preventDefault();
+    }
 
     raf.cancel(nextFrameRef.current);
+
     offsetRef.current += event.deltaY;
+    wheelValueRef.current = event.deltaY;
 
     nextFrameRef.current = raf(() => {
-      onWheelDelta(offsetRef.current);
+      // Patch a multiple for Firefox to fix wheel number too small
+      // ref: https://github.com/ant-design/ant-design/issues/26372#issuecomment-679460266
+      const patchMultiple = isMouseScrollRef.current ? 10 : 1;
+      onWheelDelta(offsetRef.current * patchMultiple);
       offsetRef.current = 0;
     });
   }
 
-  return onWheel;
+  // A patch for firefox
+  function onFireFoxScroll(event: FireFoxDOMMouseScrollEvent) {
+    if (!inVirtual) return;
+
+    // Firefox level stop
+    event.preventDefault();
+
+    isMouseScrollRef.current = event.detail === wheelValueRef.current;
+  }
+
+  return [onWheel, onFireFoxScroll];
 }
diff --git a/src/utils/isFirefox.ts b/src/utils/isFirefox.ts
new file mode 100644
index 00000000..f4271cec
--- /dev/null
+++ b/src/utils/isFirefox.ts
@@ -0,0 +1,2 @@
+const isFF = /Firefox/i.test(navigator.userAgent);
+export default isFF;

From 8ae481ac1a723173200787f3baae035e40965198 Mon Sep 17 00:00:00 2001
From: zombiej <smith3816@gmail.com>
Date: Tue, 25 Aug 2020 15:05:26 +0800
Subject: [PATCH 2/2] add test case

---
 tests/scroll-Firefox.test.js | 82 ++++++++++++++++++++++++++++++++++++
 1 file changed, 82 insertions(+)
 create mode 100644 tests/scroll-Firefox.test.js

diff --git a/tests/scroll-Firefox.test.js b/tests/scroll-Firefox.test.js
new file mode 100644
index 00000000..ce50aab4
--- /dev/null
+++ b/tests/scroll-Firefox.test.js
@@ -0,0 +1,82 @@
+import React from 'react';
+import { act } from 'react-dom/test-utils';
+import { mount } from 'enzyme';
+import { spyElementPrototypes } from './utils/domHook';
+import List from '../src';
+import isFF from '../src/utils/isFirefox';
+
+function genData(count) {
+  return new Array(count).fill(null).map((_, index) => ({ id: String(index) }));
+}
+
+jest.mock('../src/utils/isFirefox', () => true);
+
+describe('List.Firefox-Scroll', () => {
+  let mockElement;
+
+  beforeAll(() => {
+    mockElement = spyElementPrototypes(HTMLElement, {
+      offsetHeight: {
+        get: () => 20,
+      },
+      clientHeight: {
+        get: () => 100,
+      },
+    });
+  });
+
+  afterAll(() => {
+    mockElement.mockRestore();
+  });
+
+  beforeEach(() => {
+    jest.useFakeTimers();
+  });
+
+  afterEach(() => {
+    jest.useRealTimers();
+  });
+
+  function genList(props) {
+    let node = (
+      <List component="ul" itemKey="id" {...props}>
+        {({ id }) => <li>{id}</li>}
+      </List>
+    );
+
+    if (props.ref) {
+      node = <div>{node}</div>;
+    }
+
+    return mount(node);
+  }
+
+  it('should be true', () => {
+    expect(isFF).toBe(true);
+  });
+
+  // https://github.com/ant-design/ant-design/issues/26372
+  it('FireFox should patch scroll speed', () => {
+    const wheelPreventDefault = jest.fn();
+    const firefoxPreventDefault = jest.fn();
+    const wrapper = genList({ itemHeight: 20, height: 100, data: genData(100) });
+    const ulElement = wrapper.find('ul').instance();
+
+    act(() => {
+      const wheelEvent = new Event('wheel');
+      wheelEvent.deltaY = 3;
+      wheelEvent.preventDefault = wheelPreventDefault;
+      ulElement.dispatchEvent(wheelEvent);
+
+      const firefoxScrollEvent = new Event('DOMMouseScroll');
+      firefoxScrollEvent.detail = 3;
+      firefoxScrollEvent.preventDefault = firefoxPreventDefault;
+      ulElement.dispatchEvent(firefoxScrollEvent);
+
+      jest.runAllTimers();
+    });
+
+    expect(wheelPreventDefault).not.toHaveBeenCalled();
+    expect(firefoxPreventDefault).toHaveBeenCalled();
+  });
+});