fix: Should not crash when item remove by scroll (#90)

Author: zombieJ

examples/basic.tsx

@@ -88,6 +88,17 @@ const Demo = () => {
         >
           Scroll To 100px
         </button>
+        <button
+          type="button"
+          onClick={() => {
+            listRef.current.scrollTo({
+              index: 99999999,
+              align: 'top',
+            });
+          }}
+        >
+          Scroll To 99999999 (top)
+        </button>
         <button
           type="button"
           onClick={() => {

src/List.tsx

@@ -88,7 +88,7 @@ export function RawList<T>(props: ListProps<T>, ref: React.Ref<ListRef>) {
       if (typeof itemKey === 'function') {
         return itemKey(item);
       }
-      return item[itemKey];
+      return item?.[itemKey];
     },
     [itemKey],
   );

src/hooks/useScrollTo.tsx

@@ -58,7 +58,9 @@ export default function useScrollTo<T>(
           let itemTop = 0;
           let itemBottom = 0;
 
-          for (let i = 0; i <= index; i += 1) {
+          const maxLen = Math.min(data.length, index);
+
+          for (let i = 0; i <= maxLen; i += 1) {
             const key = getKey(data[i]);
             itemTop = stackTop;
             const cacheHeight = heights.get(key);

tests/scroll.test.js

@@ -77,10 +77,19 @@ describe('List.Scroll', () => {
     const listRef = React.createRef();
     const wrapper = genList({ itemHeight: 20, height: 100, data: genData(100), ref: listRef });
 
-    it('index scroll', () => {
-      listRef.current.scrollTo({ index: 30, align: 'top' });
-      jest.runAllTimers();
-      expect(wrapper.find('ul').instance().scrollTop).toEqual(600);
+    describe('index scroll', () => {
+      it('work', () => {
+        listRef.current.scrollTo({ index: 30, align: 'top' });
+        jest.runAllTimers();
+        expect(wrapper.find('ul').instance().scrollTop).toEqual(600);
+      });
+
+      it('out of range should not crash', () => {
+        expect(() => {
+          listRef.current.scrollTo({ index: 99999999999, align: 'top' });
+          jest.runAllTimers();
+        }).not.toThrow();
+      });
     });
 
     it('scroll top should not out of range', () => {