support dynamic height rows for non-virtualized rendering

README.md

@@ -881,7 +881,7 @@ function MyGrid() {
 
 Function to generate unique IDs for group rows. If not provided, a default implementation is used that concatenates parent and group keys with `__`.
 
-###### `rowHeight?: Maybe<number | ((args: RowHeightArgs<R>) => number)>`
+###### `rowHeight?: Maybe<number | string | ((args: RowHeightArgs<R>) => number)>`
 
 **Note:** Unlike `DataGrid`, the `rowHeight` function receives [`RowHeightArgs<R>`](#rowheightargstrow) which includes a `type` property to distinguish between regular rows and group rows:
 

src/DataGrid.tsx

@@ -1,10 +1,13 @@
-import { useCallback, useImperativeHandle, useMemo, useRef, useState } from 'react';
 import type { Key, KeyboardEvent } from 'react';
+import { useCallback, useImperativeHandle, useMemo, useRef, useState } from 'react';
 import { flushSync } from 'react-dom';
 
 import {
+  type ActivePosition,
   HeaderRowSelectionChangeContext,
   HeaderRowSelectionContext,
+  type HeaderRowSelectionContextValue,
+  type PartialPosition,
   RowSelectionChangeContext,
   useActivePosition,
   useCalculatedColumns,
@@ -14,10 +17,7 @@ import {
   useScrollState,
   useScrollToPosition,
   useViewportColumns,
-  useViewportRows,
-  type ActivePosition,
-  type HeaderRowSelectionContextValue,
-  type PartialPosition
+  useViewportRows
 } from './hooks';
 import {
   assertIsValidKeyGetter,
@@ -45,19 +45,19 @@ import type {
   CellMouseEventHandler,
   CellNavigationMode,
   CellPasteArgs,
-  PositionChangeArgs,
   Column,
   ColumnOrColumnGroup,
   ColumnWidths,
   Direction,
   FillEvent,
   Maybe,
   Position,
+  PositionChangeArgs,
   Renderers,
   RowsChangeData,
-  SetActivePositionOptions,
   SelectHeaderRowEvent,
   SelectRowEvent,
+  SetActivePositionOptions,
   SortColumn
 } from './types';
 import { defaultRenderCell } from './Cell';
@@ -73,10 +73,10 @@ import { defaultRenderRow } from './Row';
 import { default as defaultRenderSortStatus } from './sortStatus';
 import { cellDragHandleClassname, cellDragHandleFrozenClassname } from './style/cell';
 import {
-  rootClassname,
   frozenColumnShadowClassname,
-  viewportDraggingClassname,
-  frozenColumnShadowTopClassname
+  frozenColumnShadowTopClassname,
+  rootClassname,
+  viewportDraggingClassname
 } from './style/core';
 import SummaryRow from './SummaryRow';
 
@@ -136,7 +136,7 @@ export interface DataGridProps<R, SR = unknown, K extends Key = Key> extends Sha
    * Height of each row in pixels
    * @default 35
    */
-  rowHeight?: Maybe<number | ((row: NoInfer<R>) => number)>;
+  rowHeight?: Maybe<number | string | ((row: NoInfer<R>) => number)>;
   /**
    * Height of the header row in pixels
    * @default 35
@@ -301,9 +301,13 @@ export function DataGrid<R, SR = unknown, K extends Key = Key>(props: DataGridPr
   const renderCheckbox =
     renderers?.renderCheckbox ?? defaultRenderers?.renderCheckbox ?? defaultRenderCheckbox;
   const noRowsFallback = renderers?.noRowsFallback ?? defaultRenderers?.noRowsFallback;
-  const enableVirtualization = rawEnableVirtualization ?? true;
+  const enableVirtualization = rawEnableVirtualization ?? typeof rawRowHeight !== 'string';
   const direction = rawDirection ?? 'ltr';
 
+  if (enableVirtualization && typeof rowHeight === 'string') {
+    throw new Error('`rowHeight` cannot be a string when `enableVirtualization` is true.');
+  }
+
   /**
    * ref
    */
@@ -404,7 +408,9 @@ export function DataGrid<R, SR = unknown, K extends Key = Key>(props: DataGridPr
     maxRowIdx,
     setDraggedOverRowIdx
   });
-  const { setScrollToPosition, scrollToPositionElement } = useScrollToPosition({ gridRef });
+  const { setScrollToPosition, scrollToPositionElement } = useScrollToPosition({
+    gridRef
+  });
 
   const defaultGridComponents = useMemo(
     () => ({
@@ -448,10 +454,16 @@ export function DataGrid<R, SR = unknown, K extends Key = Key>(props: DataGridPr
     findRowIdx
   } = useViewportRows({
     rows,
-    rowHeight,
     clientHeight,
     scrollTop,
-    enableVirtualization
+    enableVirtualization,
+    ...(typeof rowHeight === 'string'
+      ? {
+          rowHeight,
+          element: gridRef.current,
+          gridHeight
+        }
+      : { rowHeight })
   });
 
   const {
@@ -674,7 +686,11 @@ export function DataGrid<R, SR = unknown, K extends Key = Key>(props: DataGridPr
     if (isSelectable && shiftKey && key === ' ') {
       assertIsValidKeyGetter<R, K>(rowKeyGetter);
       const rowKey = rowKeyGetter(row);
-      selectRow({ row, checked: !selectedRows.has(rowKey), isShiftClick: false });
+      selectRow({
+        row,
+        checked: !selectedRows.has(rowKey),
+        isShiftClick: false
+      });
       // prevent scrolling
       event.preventDefault();
       return;
@@ -760,7 +776,11 @@ export function DataGrid<R, SR = unknown, K extends Key = Key>(props: DataGridPr
     const indexes: number[] = [];
     for (let i = startRowIdx; i < endRowIdx; i++) {
       if (isCellEditable({ rowIdx: i, idx })) {
-        const updatedRow = onFill!({ columnKey: column.key, sourceRow, targetRow: rows[i] });
+        const updatedRow = onFill!({
+          columnKey: column.key,
+          sourceRow,
+          targetRow: rows[i]
+        });
         if (updatedRow !== rows[i]) {
           updatedRows[i] = updatedRow;
           indexes.push(i);
@@ -978,10 +998,17 @@ export function DataGrid<R, SR = unknown, K extends Key = Key>(props: DataGridPr
 
     const { row } = activePosition;
     const column = getActiveColumn();
-    const colSpan = getColSpan(column, lastFrozenColumnIndex, { type: 'ROW', row });
+    const colSpan = getColSpan(column, lastFrozenColumnIndex, {
+      type: 'ROW',
+      row
+    });
 
     function closeEditor(shouldFocus: boolean) {
-      const newPosition: ActivePosition = { idx: activePosition.idx, rowIdx, mode: 'ACTIVE' };
+      const newPosition: ActivePosition = {
+        idx: activePosition.idx,
+        rowIdx,
+        mode: 'ACTIVE'
+      };
       setActivePosition(newPosition);
       if (shouldFocus) {
         setPositionToFocus(newPosition);

src/hooks/useViewportRows.ts

@@ -2,20 +2,33 @@
 
 import { floor, max, min } from '../utils';
 
-interface ViewportRowsArgs<R> {
+interface ViewportRowsBaseArgs<R> {
   rows: readonly R[];
-  rowHeight: number | ((row: R) => number);
   clientHeight: number;
   scrollTop: number;
   enableVirtualization: boolean;
 }
 
+interface ViewportRowsArgsStringHeight {
+  rowHeight: string;
+  element: HTMLElement | null;
+  gridHeight: number;
+}
+
+interface ViewportRowsArgsRegularHeight<R> {
+  rowHeight: number | ((row: R) => number);
+}
+
+type ViewportRowsArgs<R> = ViewportRowsBaseArgs<R> &
+  (ViewportRowsArgsStringHeight | ViewportRowsArgsRegularHeight<R>);
+
 export function useViewportRows<R>({
   rows,
   rowHeight,
   clientHeight,
   scrollTop,
-  enableVirtualization
+  enableVirtualization,
+  ...rest
 }: ViewportRowsArgs<R>) {
   const { totalRowHeight, gridTemplateRows, getRowTop, getRowHeight, findRowIdx } = useMemo(() => {
     if (typeof rowHeight === 'number') {
@@ -28,6 +41,71 @@
       };
     }
 
+    if (typeof rowHeight === 'string') {
+      const { element, gridHeight } = rest as ViewportRowsArgsStringHeight;
+      if (!element) {
+        throw new Error(
+          'props.element is required when rowHeight is a string. This is needed to calculate the position of the rows.'
+        );
+      }
+      if (!gridHeight) {
+        throw new Error(
+          'props.gridHeight is required when rowHeight is a string. This is needed to calculate the total height of the rows.'
+        );
+      }
+
+      const getRowElementFirstCell = (element: Element, rowIdx: number): Element | null => {
+        const nth = element.querySelector('.rdg-header-row') ? rowIdx + 2 : rowIdx + 1;
+        return element.querySelector(`[role="row"][aria-rowindex="${nth}"] > [role="gridcell"]`);
+      };
+
+      const getRowYTop = (element: Element, rowIdx: number) => {
+        const cell = getRowElementFirstCell(element, rowIdx);
+        if (!cell) return -1;
+        return cell.getBoundingClientRect().top + element.scrollTop;
+      };
+
+      return {
+        totalRowHeight: gridHeight ?? 0,
+        gridTemplateRows: ` repeat(${rows.length}, ${rowHeight})`,
+        getRowTop(rowIdx: number) {
+          if (!element) return -1;
+          const cell = getRowElementFirstCell(element, rowIdx);
+          if (!cell) return -1;
+          return cell.getBoundingClientRect().top + element.scrollTop;
+        },
+        getRowHeight(rowIdx: number) {
+          if (!element) return -1;
+          const cell = getRowElementFirstCell(element, rowIdx);
+          if (!cell) return -1;
+          return cell.clientHeight;
+        },
+        findRowIdx(offset: number) {
+          if (!element) return -1;
+          let start = 0;
+          let end = rows.length - 1;
+
+          while (start <= end) {
+            const middle = start + floor((end - start) / 2);
+            const currentScrollTop = getRowYTop(element, middle);
+            const prevScrollTop = getRowYTop(element, middle - 1);
+
+            if (currentScrollTop >= offset && prevScrollTop < offset) return middle;
+
+            if (currentScrollTop < offset) {
+              start = middle + 1;
+            } else if (currentScrollTop > offset) {
+              end = middle - 1;
+            }
+
+            if (start > end) return end;
+          }
+
+          return -1;
+        }
+      };
+    }
+
     // Calcule the height of all the rows upfront. This can cause performance issues
     // and we can consider using a similar approach as react-window
     // https://github.com/bvaughn/react-window/blob/b0a470cc264e9100afcaa1b78ed59d88f7914ad4/src/VariableSizeList.js#L68
@@ -102,7 +180,7 @@
         return 0;
       }
     };
-  }, [rowHeight, rows]);
+  }, [element, gridHeight, rowHeight, rows]);
 
   let rowOverscanStartIdx = 0;
   let rowOverscanEndIdx = rows.length - 1;

test/browser/rowHeight.test.ts → test/browser/rowHeight.test.tsx

@@ -102,3 +102,64 @@ test('rowHeight with unique first height', async () => {
     return row === 0 ? 45 : 50;
   }, 'repeat(1, 35px) 45px repeat(49, 50px)');
 });
+
+test('rowHeight is "auto" sets gridTemplateRows to repeat(N, auto)', async () => {
+  await setupGrid('auto');
+
+  expect(grid.element().style.gridTemplateRows).toBe('repeat(1, 35px) repeat(50, auto)');
+});
+
+test('rowHeight as a string auto-disables virtualization and renders all rows', async () => {
+  await setupGrid('auto');
+
+  // virtualization is off by default when `rowHeight` is a string,
+  // so every row is rendered regardless of viewport size
+  await testRowCount(50);
+});
+
+test('rowHeight accepts arbitrary CSS track values', async () => {
+  await setupGrid('min-content');
+
+  expect(grid.element().style.gridTemplateRows).toBe('repeat(1, 35px) repeat(50, min-content)');
+  await testRowCount(50);
+});
+
+test('rowHeight is "auto" sizes rows to fit their content', async () => {
+  const columns: Column<{ id: number; content: string }>[] = [
+    { key: 'id', name: 'ID', width: 80 },
+    {
+      key: 'content',
+      name: 'Content',
+      width: 200,
+      renderCell: ({ row }) => <div style={{ whiteSpace: 'pre' }}>{row.content}</div>
+    }
+  ];
+  const rows = [
+    { id: 0, content: 'short' },
+    { id: 1, content: 'line one\nline two\nline three\nline four' }
+  ];
+
+  await setup({ columns, rows, rowHeight: 'auto' });
+
+  const row0 = page.getRow().nth(0).element() as HTMLElement;
+  const row1 = page.getRow().nth(1).element() as HTMLElement;
+
+  // multi-line cell must render taller than the single-line cell
+  expect(row1.clientHeight).toBeGreaterThan(row0.clientHeight);
+});
+
+test('rowHeight string + explicit enableVirtualization=true throws', async () => {
+  // Suppress React's error logging for this expected render error
+  vi.mocked(console.error).mockImplementation(() => {});
+
+  await expect(
+    setup({
+      columns: [{ key: 'id', name: 'ID' }],
+      rows: [{ id: 0 }],
+      rowHeight: 'auto',
+      enableVirtualization: true
+    })
+  ).rejects.toThrow('`rowHeight` cannot be a string when `enableVirtualization` is true.');
+
+  vi.mocked(console.error).mockClear();
+});

website/Nav.tsx

@@ -91,6 +91,7 @@ export default function Nav({ direction, onDirectionChange }: Props) {
         <Link to="/ColumnsReordering">Columns Reordering</Link>
         <Link to="/ContextMenu">Context Menu</Link>
         <Link to="/CustomizableRenderers">Customizable Renderers</Link>
+        <Link to="/DynamicHeightCells">Dynamic Height Cells</Link>
         <Link to="/RowGrouping">Row Grouping</Link>
         <Link to="/HeaderFilters">Header Filters</Link>
         <Link to="/InfiniteScrolling">Infinite Scrolling</Link>