From 8b6def94f65f93767a566b7b1d954e8c0bf62ec3 Mon Sep 17 00:00:00 2001
From: hamed-musallam <35760236+hamed-musallam@users.noreply.github.com>
Date: Thu, 10 Nov 2022 14:50:24 +0100
Subject: [PATCH] fix: react table virtual scroll (#1879)

* fix: react table virtual scroll

close #1863
---
 .../elements/ReactTable/ReactTable.tsx        | 96 ++++++++-----------
 .../ReactTable/utility/ReactTableContext.ts   |  4 +-
 2 files changed, 42 insertions(+), 58 deletions(-)

diff --git a/src/component/elements/ReactTable/ReactTable.tsx b/src/component/elements/ReactTable/ReactTable.tsx
index 46ab6ba78..8a2d2abf5 100644
--- a/src/component/elements/ReactTable/ReactTable.tsx
+++ b/src/component/elements/ReactTable/ReactTable.tsx
@@ -2,14 +2,13 @@
 /** @jsxImportSource @emotion/react */
 import {
   useRef,
-  useCallback,
   memo,
   forwardRef,
   useState,
   Ref,
-  useEffect,
-  UIEvent,
   CSSProperties,
+  WheelEvent,
+  useLayoutEffect,
 } from 'react';
 import { useTable, useSortBy } from 'react-table';
 import { useMeasure } from 'react-use';
@@ -41,7 +40,7 @@ interface ReactTableProps extends ClickEvent {
 }
 
 interface ReactTableInnerProps extends ReactTableProps {
-  onScroll: (event: UIEvent<HTMLDivElement>) => void;
+  onScroll: (event: WheelEvent<HTMLDivElement>) => void;
 }
 
 const styles = {
@@ -84,7 +83,7 @@ const ReactTableInner = forwardRef(function ReactTableInner(
   } = props;
 
   const contextRef = useRef<any>(null);
-  const { index: indexBoundary } = useReactTableContext();
+  const virtualBoundary = useReactTableContext();
   const [rowIndex, setRowIndex] = useState<number>();
   const timeoutIdRef = useRef<NodeJS.Timeout>();
   const [isCounterVisible, setCounterVisibility] = useState(false);
@@ -104,27 +103,17 @@ const ReactTableInner = forwardRef(function ReactTableInner(
     useSortBy,
     useRowSpan,
   );
-  const contextMenuHandler = useCallback(
-    (e, row) => {
-      if (!checkModifierKeyActivated(e)) {
-        e.preventDefault();
-        contextRef.current.handleContextMenu(e, row.original);
-      }
-    },
-    [contextRef],
-  );
-
-  const rowsData = enableVirtualScroll
-    ? rows.slice(indexBoundary.start, indexBoundary.end)
-    : rows;
+  function contextMenuHandler(e, row) {
+    if (!checkModifierKeyActivated(e)) {
+      e.preventDefault();
+      contextRef.current.handleContextMenu(e, row.original);
+    }
+  }
 
-  const clickHandler = useCallback(
-    (event, row) => {
-      setRowIndex(row.index);
-      onClick?.(event, row);
-    },
-    [onClick],
-  );
+  function clickHandler(event, row) {
+    setRowIndex(row.index);
+    onClick?.(event, row);
+  }
 
   function scrollHandler(e) {
     if (enableVirtualScroll) {
@@ -141,6 +130,14 @@ const ReactTableInner = forwardRef(function ReactTableInner(
     }, 1000);
   }
 
+  const end =
+    virtualBoundary.end === rows.length - 1
+      ? virtualBoundary.end + 1
+      : virtualBoundary.end;
+  const rowsData = enableVirtualScroll
+    ? rows.slice(virtualBoundary.start, end)
+    : rows;
+
   const index =
     rowsData[rowsData.length - 1]?.original[indexKey] ||
     rowsData[rowsData.length - 1]?.index;
@@ -161,7 +158,7 @@ const ReactTableInner = forwardRef(function ReactTableInner(
         {enableVirtualScroll && (
           <div
             style={{
-              height: approxItemHeight * data.length,
+              height: approxItemHeight * (data.length + 1),
               position: 'absolute',
               width: '100%',
               pointerEvents: 'none',
@@ -180,7 +177,7 @@ const ReactTableInner = forwardRef(function ReactTableInner(
 
               prepareRowSpan(
                 rows,
-                enableVirtualScroll ? index + indexBoundary.start : index,
+                enableVirtualScroll ? index + virtualBoundary.start : index,
                 rowSpanHeaders,
                 groupKey,
               );
@@ -217,37 +214,30 @@ const ReactTableInner = forwardRef(function ReactTableInner(
   );
 });
 
-export interface TableVirtualConfig {
-  scrollHeight: number;
-  numberOfVisibleRows: number;
-  index: { start: number; end: number };
+export interface TableVirtualBoundary {
+  start: number;
+  end: number;
 }
 
 function ReactTable(props: ReactTableProps) {
   const { data, approxItemHeight = 40, groupKey } = props;
   const containerRef = useRef<HTMLDivElement | null>(null);
+  const visibleRowsCountRef = useRef<number>(0);
   const [mRef, { height }] = useMeasure<HTMLDivElement>();
 
-  const [tableVirtualConfig, setTableVirtualConfig] =
-    useState<TableVirtualConfig>({
-      scrollHeight: 0,
-      numberOfVisibleRows: 0,
-      index: { start: 0, end: 0 },
+  const [tableVirtualBoundary, setTableVirtualBoundary] =
+    useState<TableVirtualBoundary>({
+      start: 1,
+      end: 0,
     });
 
-  useEffect(() => {
+  useLayoutEffect(() => {
     if (containerRef.current) {
-      const { scrollHeight } = containerRef.current;
       const header = containerRef.current.querySelectorAll('thead');
-      const numberOfVisibleRows = Math.ceil(
+      visibleRowsCountRef.current = Math.ceil(
         (height - header[0].clientHeight) / approxItemHeight,
       );
-      setTableVirtualConfig((prev) => ({
-        ...prev,
-        scrollHeight,
-        numberOfVisibleRows: numberOfVisibleRows - 1,
-        index: { start: 0, end: numberOfVisibleRows },
-      }));
+      setTableVirtualBoundary({ start: 0, end: visibleRowsCountRef.current });
     }
   }, [approxItemHeight, height]);
 
@@ -300,23 +290,17 @@ function ReactTable(props: ReactTableProps) {
   }
 
   function scrollHandler() {
-    if (containerRef.current && tableVirtualConfig) {
+    if (containerRef.current) {
       const { scrollTop } = containerRef.current;
-      const { numberOfVisibleRows, index } = tableVirtualConfig;
       const currentIndx = Math.ceil(scrollTop / approxItemHeight);
-      const start = findStartIndex(currentIndx, numberOfVisibleRows);
-      if (currentIndx !== index.start) {
-        const end = findEndIndex(currentIndx, numberOfVisibleRows);
-        setTableVirtualConfig({
-          ...tableVirtualConfig,
-          index: { start, end: end + 1 },
-        });
-      }
+      const start = findStartIndex(currentIndx, visibleRowsCountRef.current);
+      const end = findEndIndex(currentIndx, visibleRowsCountRef.current);
+      setTableVirtualBoundary({ start, end });
     }
   }
 
   return (
-    <ReactTableProvider value={tableVirtualConfig}>
+    <ReactTableProvider value={tableVirtualBoundary}>
       <div
         ref={mRef}
         style={{
diff --git a/src/component/elements/ReactTable/utility/ReactTableContext.ts b/src/component/elements/ReactTable/utility/ReactTableContext.ts
index 7dbc7f977..8dd1b8448 100644
--- a/src/component/elements/ReactTable/utility/ReactTableContext.ts
+++ b/src/component/elements/ReactTable/utility/ReactTableContext.ts
@@ -1,8 +1,8 @@
 import { createContext, useContext } from 'react';
 
-import { TableVirtualConfig } from '../ReactTable';
+import { TableVirtualBoundary } from '../ReactTable';
 
-const reactContext = createContext<TableVirtualConfig | null>(null);
+const reactContext = createContext<TableVirtualBoundary | null>(null);
 export const ReactTableProvider = reactContext.Provider;
 
 export function useReactTableContext() {