From c7aa83f8d3ef01d64538e83405addfde0ff4daf2 Mon Sep 17 00:00:00 2001
From: Leon Sorokin <leeoniya@gmail.com>
Date: Wed, 16 Jul 2025 19:11:28 -0500
Subject: [PATCH] TableNG: Use Set for tracking expanded rows (#108198)

---
 .../src/components/Table/TableNG/TableNG.tsx  | 22 ++++++++++---------
 .../src/components/Table/TableNG/hooks.ts     |  6 ++---
 .../src/components/Table/TableNG/utils.ts     |  6 ++---
 3 files changed, 18 insertions(+), 16 deletions(-)

diff --git a/packages/grafana-ui/src/components/Table/TableNG/TableNG.tsx b/packages/grafana-ui/src/components/Table/TableNG/TableNG.tsx
index ea128eddafb..012424e1e28 100644
--- a/packages/grafana-ui/src/components/Table/TableNG/TableNG.tsx
+++ b/packages/grafana-ui/src/components/Table/TableNG/TableNG.tsx
@@ -159,7 +159,7 @@ export function TableNG(props: TableNGProps) {
   const defaultRowHeight = getDefaultRowHeight(theme, cellHeight);
   const defaultHeaderHeight = getDefaultRowHeight(theme, TableCellHeight.Sm);
   const [isInspecting, setIsInspecting] = useState(false);
-  const [expandedRows, setExpandedRows] = useState<Record<string, boolean>>({});
+  const [expandedRows, setExpandedRows] = useState(() => new Set<number>());
 
   // vt scrollbar accounting for column auto-sizing
   const visibleFields = useMemo(() => getVisibleFields(data.fields), [data.fields]);
@@ -517,12 +517,19 @@ export function TableNG(props: TableNGProps) {
       },
       renderCell: ({ row }) => {
         if (row.__depth === 0) {
+          const rowIdx = row.__index;
+
           return (
             <RowExpander
               height={defaultRowHeight}
-              isExpanded={expandedRows[row.__index] ?? false}
+              isExpanded={expandedRows.has(rowIdx)}
               onCellExpand={() => {
-                setExpandedRows({ ...expandedRows, [row.__index]: !expandedRows[row.__index] });
+                if (expandedRows.has(rowIdx)) {
+                  expandedRows.delete(rowIdx);
+                } else {
+                  expandedRows.add(rowIdx);
+                }
+                setExpandedRows(new Set(expandedRows));
               }}
             />
           );
@@ -710,16 +717,11 @@ export function TableNG(props: TableNGProps) {
  * this is passed to the top-level `renderRow` prop on DataGrid. applies aria attributes and custom event handlers.
  */
 const renderRowFactory =
-  (
-    fields: Field[],
-    panelContext: PanelContext,
-    expandedRows: Record<string, boolean>,
-    enableSharedCrosshair: boolean
-  ) =>
+  (fields: Field[], panelContext: PanelContext, expandedRows: Set<number>, enableSharedCrosshair: boolean) =>
   (key: React.Key, props: RenderRowProps<TableRow, TableSummaryRow>): React.ReactNode => {
     const { row } = props;
     const rowIdx = row.__index;
-    const isExpanded = !!expandedRows[rowIdx];
+    const isExpanded = expandedRows.has(rowIdx);
 
     // Don't render non expanded child rows
     if (row.__depth === 1 && !isExpanded) {
diff --git a/packages/grafana-ui/src/components/Table/TableNG/hooks.ts b/packages/grafana-ui/src/components/Table/TableNG/hooks.ts
index c4bcabe0828..252eb362e14 100644
--- a/packages/grafana-ui/src/components/Table/TableNG/hooks.ts
+++ b/packages/grafana-ui/src/components/Table/TableNG/hooks.ts
@@ -441,7 +441,7 @@ interface UseRowHeightOptions {
   hasNestedFrames: boolean;
   defaultHeight: number;
   headerHeight: number;
-  expandedRows: Record<string, boolean>;
+  expandedRows: Set<number>;
   typographyCtx: TypographyCtx;
 }
 
@@ -497,9 +497,9 @@ export function useRowHeight({
 
     return (row: TableRow) => {
       // nested rows
-      if (Number(row.__depth) > 0) {
+      if (row.__depth > 0) {
         // if unexpanded, height === 0
-        if (!expandedRows[row.__index]) {
+        if (!expandedRows.has(row.__index)) {
           return 0;
         }
 
diff --git a/packages/grafana-ui/src/components/Table/TableNG/utils.ts b/packages/grafana-ui/src/components/Table/TableNG/utils.ts
index 1cd6d279856..191e9fa76e4 100644
--- a/packages/grafana-ui/src/components/Table/TableNG/utils.ts
+++ b/packages/grafana-ui/src/components/Table/TableNG/utils.ts
@@ -512,10 +512,10 @@ export const processNestedTableRows = (
   const childRows: Map<number, TableRow> = new Map();
 
   for (const row of rows) {
-    if (Number(row.__depth) === 0) {
+    if (row.__depth === 0) {
       parentRows.push(row);
     } else {
-      childRows.set(Number(row.__index), row);
+      childRows.set(row.__index, row);
     }
   }
 
@@ -526,7 +526,7 @@ export const processNestedTableRows = (
   const result: TableRow[] = [];
   processedParents.forEach((row) => {
     result.push(row);
-    const childRow = childRows.get(Number(row.__index));
+    const childRow = childRows.get(row.__index);
     if (childRow) {
       result.push(childRow);
     }