feat: support render get size (#217)

* feat: support render get size

* feat: get from key range

* test: update snapshot

Author: zombieJ

examples/horizontal-scroll.tsx

@@ -2,7 +2,7 @@ import * as React from 'react';
 import List from '../src/List';
 
 interface Item {
-  id: number;
+  id: string;
   height: number;
 }
 
@@ -72,7 +72,7 @@ const ForwardMyItem = React.forwardRef(MyItem);
 const data: Item[] = [];
 for (let i = 0; i < 1000; i += 1) {
   data.push({
-    id: i,
+    id: `id_${i}`,
     height: 30 + Math.random() * 10,
   });
 }
@@ -105,12 +105,14 @@ const Demo = () => {
             }}
             extraRender={(info) => {
               const { offsetX, rtl: isRTL } = info;
+              const sizeInfo = info.getSize('id_3', 'id_5');
 
               return (
                 <div
                   style={{
                     position: 'absolute',
-                    top: 100,
+                    top: sizeInfo.top,
+                    height: sizeInfo.bottom - sizeInfo.top,
                     [isRTL ? 'right' : 'left']: 100 - offsetX,
                     background: 'rgba(255,0,0,0.1)',
                   }}

src/List.tsx

@@ -449,6 +449,42 @@ export function RawList<T>(props: ListProps<T>, ref: React.Ref<ListRef>) {
     }
   }, [start, end, mergedData]);
 
+  // ================================ Extra =================================
+  const getSize = (startKey: React.Key, endKey = startKey) => {
+    let top = 0;
+    let bottom = 0;
+    let total = 0;
+
+    const dataLen = mergedData.length;
+    for (let i = 0; i < dataLen; i += 1) {
+      const item = mergedData[i];
+      const key = getKey(item);
+
+      const cacheHeight = heights.get(key) ?? itemHeight;
+      bottom = total + cacheHeight;
+
+      if (key === startKey) {
+        top = total;
+      }
+      if (key === endKey) {
+        break;
+      }
+
+      total = bottom;
+    }
+
+    return { top, bottom };
+  };
+
+  const extraContent = extraRender?.({
+    start,
+    end,
+    virtual: inVirtual,
+    offsetX: offsetLeft,
+    rtl: isRTL,
+    getSize,
+  });
+
   // ================================ Render ================================
   const listChildren = useChildren(
     mergedData,
@@ -460,14 +496,6 @@ export function RawList<T>(props: ListProps<T>, ref: React.Ref<ListRef>) {
     sharedConfig,
   );
 
-  const extraContent = extraRender?.({
-    start,
-    end,
-    virtual: inVirtual,
-    offsetX: offsetLeft,
-    rtl: isRTL,
-  });
-
   let componentStyle: React.CSSProperties = null;
   if (height) {
     componentStyle = { [fullHeight ? 'height' : 'maxHeight']: height, ...ScrollStyle };

src/interface.ts

@@ -21,4 +21,6 @@ export interface ExtraRenderInfo {
   offsetX: number;
 
   rtl: boolean;
+
+  getSize: (startKey: React.Key, endKey?: React.Key) => { top: number; bottom: number };
 }

tests/scrollWidth.test.tsx

@@ -7,6 +7,8 @@ import List, { type ListProps } from '../src';
 import { _rs as onLibResize } from 'rc-resize-observer/lib/utils/observerUtil';
 import '@testing-library/jest-dom';
 
+const ITEM_HEIGHT = 20;
+
 function genData(count) {
   return new Array(count).fill(null).map((_, index) => ({ id: String(index) }));
 }
@@ -19,7 +21,7 @@ describe('List.scrollWidth', () => {
   beforeAll(() => {
     mockElement = spyElementPrototypes(HTMLElement, {
       offsetHeight: {
-        get: () => 20,
+        get: () => ITEM_HEIGHT,
       },
       clientHeight: {
         get: () => 100,
@@ -73,7 +75,7 @@ describe('List.scrollWidth', () => {
 
   it('work', async () => {
     const { container } = await genList({
-      itemHeight: 20,
+      itemHeight: ITEM_HEIGHT,
       height: 100,
       data: genData(100),
       scrollWidth: 1000,
@@ -88,7 +90,7 @@ describe('List.scrollWidth', () => {
       const listRef = React.createRef<ListRef>();
 
       const { container } = await genList({
-        itemHeight: 20,
+        itemHeight: ITEM_HEIGHT,
         height: 100,
         data: genData(100),
         scrollWidth: 1000,
@@ -136,7 +138,7 @@ describe('List.scrollWidth', () => {
       const onVirtualScroll = jest.fn();
 
       const { container } = await genList({
-        itemHeight: 20,
+        itemHeight: ITEM_HEIGHT,
         height: 100,
         data: genData(100),
         scrollWidth: 1000,
@@ -155,7 +157,7 @@ describe('List.scrollWidth', () => {
     const listRef = React.createRef<ListRef>();
 
     await genList({
-      itemHeight: 20,
+      itemHeight: ITEM_HEIGHT,
       height: 100,
       data: genData(100),
       scrollWidth: 1000,
@@ -171,13 +173,22 @@ describe('List.scrollWidth', () => {
 
   it('support extraRender', async () => {
     const { container } = await genList({
-      itemHeight: 20,
+      itemHeight: ITEM_HEIGHT,
       height: 100,
       data: genData(100),
       scrollWidth: 1000,
-      extraRender: () => <div className="bamboo" />,
+      extraRender: ({ getSize }) => {
+        const size = getSize('1', '3');
+        return (
+          <div className="bamboo">
+            {size.top}/{size.bottom}
+          </div>
+        );
+      },
     });
 
-    expect(container.querySelector('.bamboo')).toBeTruthy();
+    expect(container.querySelector('.bamboo').textContent).toEqual(
+      `${ITEM_HEIGHT}/${4 * ITEM_HEIGHT}`,
+    );
   });
 });