fix: Scroll back to raw list should not crash after size change again

Author: zombieJ

examples/switch.tsx

@@ -34,7 +34,18 @@ function getData(count: number) {
 }
 
 const Demo = () => {
-  const [data, setData] = React.useState<{ id: number }[]>(getData(1));
+  const [state, setState] = React.useState<number>(0);
+
+  const data = React.useMemo(() => {
+    switch (state) {
+      case 0:
+        return getData(1000);
+      case 1:
+        return getData(2);
+      default:
+        return getData(0);
+    }
+  }, [state]);
 
   return (
     <React.StrictMode>
@@ -55,7 +66,7 @@ const Demo = () => {
         <button
           type="button"
           onClick={() => {
-            setData(data.length === 1 ? getData(10000) : getData(1));
+            setState((state + 1) % 3);
           }}
         >
           Switch

src/List.tsx

@@ -279,6 +279,7 @@ class List<T = any> extends React.Component<ListProps<T>, ListState<T>> {
 
       this.setState({
         status: 'MEASURE_DONE',
+        itemIndex: 0,
       });
 
       requestAnimationFrame(() => {

tests/list.test.js

@@ -174,10 +174,15 @@ describe('List', () => {
       });
 
       scrollHeight = 200;
-      data = data.slice(0, -1);
+      data = data.slice(0, 2);
       wrapper.setProps({ data });
       expect(wrapper.find('ul').instance().scrollTop > 40).toBeTruthy();
 
+      // Should not crash if data count change
+      scrollHeight = 40;
+      data = data.slice(0, 1);
+      wrapper.setProps({ data });
+
       setTimeout(done, 50);
     });
   });