Add support for variable row heights

src/DataGrid.tsx

@@ -40,7 +40,8 @@ import type {
   FillEvent,
   PasteEvent,
   CellNavigationMode,
-  SortDirection
+  SortDirection,
+  RowHeightArgs
 } from './types';
 
 interface SelectCellState extends Position {
@@ -100,7 +101,7 @@ export interface DataGridProps<R, SR = unknown> extends SharedDivProps {
    * Dimensions props
    */
   /** The height of each row in pixels */
-  rowHeight?: number;
+  rowHeight?: number | ((args: RowHeightArgs<R>) => number);
   /** The height of the header row in pixels */
   headerRowHeight?: number;
   /** The height of the header filter row in pixels */
@@ -181,9 +182,9 @@ function DataGrid<R, SR>({
   onRowsChange,
   // Dimensions props
   rowHeight = 35,
-  headerRowHeight = rowHeight,
+  headerRowHeight = typeof rowHeight === 'number' ? rowHeight : 35,
   headerFiltersHeight = 45,
-  summaryRowHeight = rowHeight,
+  summaryRowHeight = typeof rowHeight === 'number' ? rowHeight : 35,
   // Feature props
   selectedRows,
   onSelectedRowsChange,
@@ -280,7 +281,17 @@ function DataGrid<R, SR>({
     enableVirtualization
   });
 
-  const { rowOverscanStartIdx, rowOverscanEndIdx, rows, rowsCount, isGroupRow } = useViewportRows({
+  const {
+    rowOverscanStartIdx,
+    rowOverscanEndIdx,
+    rows,
+    rowsCount,
+    totalRowHeight,
+    isGroupRow,
+    getRowTop,
+    getRowHeight,
+    findRowIdx
+  } = useViewportRows({
     rawRows,
     groupBy,
     rowGrouper,
@@ -335,7 +346,7 @@ function DataGrid<R, SR>({
       const { current } = gridRef;
       if (!current) return;
       current.scrollTo({
-        top: rowIdx * rowHeight,
+        top: getRowTop(rowIdx),
         behavior: 'smooth'
       });
     },
@@ -726,12 +737,14 @@ function DataGrid<R, SR>({
     }
 
     if (typeof rowIdx === 'number') {
-      if (rowIdx * rowHeight < scrollTop) {
+      const rowTop = getRowTop(rowIdx);
+      const rowHeight = getRowHeight(rowIdx);
+      if (rowTop < scrollTop) {
         // at top boundary, scroll to the row's top
-        current.scrollTop = rowIdx * rowHeight;
-      } else if ((rowIdx + 1) * rowHeight > scrollTop + clientHeight) {
+        current.scrollTop = rowTop;
+      } else if (rowTop + rowHeight > scrollTop + clientHeight) {
         // at bottom boundary, scroll the next row's top to the bottom of the viewport
-        current.scrollTop = (rowIdx + 1) * rowHeight - clientHeight;
+        current.scrollTop = rowTop + rowHeight - clientHeight;
       }
     }
   }
@@ -784,10 +797,14 @@ function DataGrid<R, SR>({
         // If row is selected then move focus to the last row.
         if (isRowSelected) return { idx, rowIdx: rows.length - 1 };
         return ctrlKey ? { idx: columns.length - 1, rowIdx: rows.length - 1 } : { idx: columns.length - 1, rowIdx };
-      case 'PageUp':
-        return { idx, rowIdx: rowIdx - Math.floor(clientHeight / rowHeight) };
-      case 'PageDown':
-        return { idx, rowIdx: rowIdx + Math.floor(clientHeight / rowHeight) };
+      case 'PageUp': {
+        const nextRowY = getRowTop(rowIdx) + getRowHeight(rowIdx) - clientHeight;
+        return { idx, rowIdx: nextRowY > 0 ? findRowIdx(nextRowY) : 0 };
+      }
+      case 'PageDown': {
+        const nextRowY = getRowTop(rowIdx) + clientHeight;
+        return { idx, rowIdx: nextRowY < totalRowHeight ? findRowIdx(nextRowY) : rows.length - 1 };
+      }
       default:
         return selectedPosition;
     }
@@ -853,7 +870,7 @@ function DataGrid<R, SR>({
         onKeyDown: handleKeyDown,
         editorProps: {
           editorPortalTarget,
-          rowHeight,
+          rowHeight: getRowHeight(selectedPosition.rowIdx),
           row: selectedPosition.row,
           onRowChange: handleEditorRowChange,
           onClose: handleOnClose
@@ -877,7 +894,7 @@ function DataGrid<R, SR>({
     let startRowIndex = 0;
     for (let rowIdx = rowOverscanStartIdx; rowIdx <= rowOverscanEndIdx; rowIdx++) {
       const row = rows[rowIdx];
-      const top = rowIdx * rowHeight + totalHeaderHeight;
+      const top = getRowTop(rowIdx) + totalHeaderHeight;
       if (isGroupRow(row)) {
         ({ startRowIndex } = row);
         rowElements.push(
@@ -893,6 +910,7 @@ function DataGrid<R, SR>({
             childRows={row.childRows}
             rowIdx={rowIdx}
             top={top}
+            height={getRowHeight(rowIdx)}
             level={row.level}
             isExpanded={row.isExpanded}
             selectedCellIdx={selectedPosition.rowIdx === rowIdx ? selectedPosition.idx : undefined}
@@ -927,6 +945,7 @@ function DataGrid<R, SR>({
           onRowClick={onRowClick}
           rowClass={rowClass}
           top={top}
+          height={getRowHeight(rowIdx)}
           copiedCellIdx={copiedCell !== null && copiedCell.row === row ? columns.findIndex(c => c.key === copiedCell.columnKey) : undefined}
           draggedOverCellIdx={getDraggedOverCellIdx(rowIdx)}
           setDraggedOverRowIdx={isDragging ? setDraggedOverRowIdx : undefined}
@@ -968,7 +987,6 @@ function DataGrid<R, SR>({
         '--header-row-height': `${headerRowHeight}px`,
         '--filter-row-height': `${headerFiltersHeight}px`,
         '--row-width': `${totalColumnWidth}px`,
-        '--row-height': `${rowHeight}px`,
         '--summary-row-height': `${summaryRowHeight}px`,
         ...layoutCssVars
       } as unknown as React.CSSProperties}
@@ -1003,7 +1021,7 @@ function DataGrid<R, SR>({
             onKeyDown={handleKeyDown}
             onFocus={onGridFocus}
           />
-          <div style={{ height: Math.max(rows.length * rowHeight, clientHeight) }} />
+          <div style={{ height: Math.max(totalRowHeight, clientHeight) }} />
           {getViewportRows()}
           {summaryRows?.map((row, rowIdx) => (
             <SummaryRow<R, SR>

src/GroupRow.tsx

@@ -1,3 +1,4 @@
+import type { CSSProperties } from 'react';
 import { memo } from 'react';
 import clsx from 'clsx';
 
@@ -13,6 +14,7 @@ export interface GroupRowRendererProps<R, SR = unknown> extends Omit<React.HTMLA
   childRows: readonly R[];
   rowIdx: number;
   top: number;
+  height: number;
   level: number;
   selectedCellIdx?: number;
   isExpanded: boolean;
@@ -29,6 +31,7 @@ function GroupedRow<R, SR>({
   childRows,
   rowIdx,
   top,
+  height,
   level,
   isExpanded,
   selectedCellIdx,
@@ -59,7 +62,10 @@ function GroupedRow<R, SR>({
         }
       )}
       onClick={selectGroup}
-      style={{ top }}
+      style={{
+        top,
+        '--row-height': `${height}px`
+      } as unknown as CSSProperties}
       {...props}
     >
       {viewportColumns.map(column => (

src/Row.tsx

@@ -1,5 +1,5 @@
 import { memo, forwardRef } from 'react';
-import type { RefAttributes } from 'react';
+import type { RefAttributes, CSSProperties } from 'react';
 import clsx from 'clsx';
 
 import { groupRowSelectedClassname, rowClassname, rowSelectedClassname } from './style';
@@ -24,6 +24,7 @@ function Row<R, SR = unknown>({
   setDraggedOverRowIdx,
   onMouseEnter,
   top,
+  height,
   onRowChange,
   selectCell,
   selectRow,
@@ -100,7 +101,10 @@ function Row<R, SR = unknown>({
       ref={ref}
       className={className}
       onMouseEnter={handleDragEnter}
-      style={{ top }}
+      style={{
+        top,
+        '--row-height': `${height}px`
+      } as unknown as CSSProperties}
       {...props}
     >
       {cells}

src/hooks/useViewportRows.ts

@@ -1,11 +1,11 @@
 import { useMemo } from 'react';
-import type { GroupRow, GroupByDictionary } from '../types';
+import type { GroupRow, GroupByDictionary, RowHeightArgs } from '../types';
 
 const RENDER_BACTCH_SIZE = 8;
 
 interface ViewportRowsArgs<R> {
   rawRows: readonly R[];
-  rowHeight: number;
+  rowHeight: number | ((args: RowHeightArgs<R>) => number);
   clientHeight: number;
   scrollTop: number;
   groupBy: readonly string[];
@@ -94,20 +94,84 @@ export function useViewportRows<R>({
     }
   }, [expandedGroupIds, groupedRows, rawRows]);
 
+  const { totalRowHeight, getRowTop, getRowHeight, findRowIdx } = useMemo(() => {
+    if (typeof rowHeight === 'number') {
+      return {
+        totalRowHeight: rowHeight * rows.length,
+        getRowTop: (rowIdx: number) => rowIdx * rowHeight,
+        getRowHeight: () => rowHeight,
+        findRowIdx: (offset: number) => Math.floor(offset / rowHeight)
+      };
+    }
+
+    let totalRowHeight = 0;
+    // 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/master/src/VariableSizeList.js#L68
+    const rowPositions = rows.map((row: R | GroupRow<R>) => {
+      const currentRowHeight = isGroupRow(row)
+        ? rowHeight({ type: 'GROUP', row })
+        : rowHeight({ type: 'ROW', row });
+      const position = { top: totalRowHeight, height: currentRowHeight };
+      totalRowHeight += currentRowHeight;
+      return position;
+    });
+
+    const validateRowIdx = (rowIdx: number) => {
+      if (rowIdx < 0) {
+        return 0;
+      }
+
+      if (rowIdx >= rows.length) {
+        return rows.length - 1;
+      }
+
+      return rowIdx;
+    };
+
+    return {
+      totalRowHeight,
+      getRowTop: (rowIdx: number) => rowPositions[validateRowIdx(rowIdx)].top,
+      getRowHeight: (rowIdx: number) => rowPositions[validateRowIdx(rowIdx)].height,
+      findRowIdx(offset: number) {
+        let start = 0;
+        let end = rowPositions.length - 1;
+        while (start <= end) {
+          const middle = start + Math.floor((end - start) / 2);
+          const currentOffset = rowPositions[middle].top;
+
+          if (currentOffset === offset) return middle;
+
+          if (currentOffset < offset) {
+            start = middle + 1;
+          } else if (currentOffset > offset) {
+            end = middle - 1;
+          }
+
+          if (start > end) return end;
+        }
+        return 0;
+      }
+    };
+  }, [isGroupRow, rowHeight, rows]);
 
   if (!enableVirtualization) {
     return {
       rowOverscanStartIdx: 0,
       rowOverscanEndIdx: rows.length - 1,
       rows,
       rowsCount,
-      isGroupRow
+      totalRowHeight,
+      isGroupRow,
+      getRowTop,
+      getRowHeight,
+      findRowIdx
     };
   }
 
   const overscanThreshold = 4;
-  const rowVisibleStartIdx = Math.floor(scrollTop / rowHeight);
-  const rowVisibleEndIdx = Math.min(rows.length - 1, Math.floor((scrollTop + clientHeight) / rowHeight));
+  const rowVisibleStartIdx = findRowIdx(scrollTop);
+  const rowVisibleEndIdx = Math.min(rows.length - 1, findRowIdx(scrollTop + clientHeight));
   const rowOverscanStartIdx = Math.max(0, Math.floor((rowVisibleStartIdx - overscanThreshold) / RENDER_BACTCH_SIZE) * RENDER_BACTCH_SIZE);
   const rowOverscanEndIdx = Math.min(rows.length - 1, Math.ceil((rowVisibleEndIdx + overscanThreshold) / RENDER_BACTCH_SIZE) * RENDER_BACTCH_SIZE);
 
@@ -116,6 +180,10 @@ export function useViewportRows<R>({
     rowOverscanEndIdx,
     rows,
     rowsCount,
-    isGroupRow
+    totalRowHeight,
+    isGroupRow,
+    getRowTop,
+    getRowHeight,
+    findRowIdx
   };
 }

src/index.ts

@@ -24,5 +24,6 @@ export type {
   PasteEvent,
   CellNavigationMode,
   SortDirection,
-  ColSpanArgs
+  ColSpanArgs,
+  RowHeightArgs
 } from './types';

src/types.ts

@@ -168,6 +168,7 @@ export interface RowRendererProps<TRow, TSummaryRow = unknown> extends Omit<Reac
   lastFrozenColumnIndex: number;
   isRowSelected: boolean;
   top: number;
+  height: number;
   selectedCellProps?: EditCellProps<TRow> | SelectedCellProps;
   onRowChange: (rowIdx: number, row: TRow) => void;
   onRowClick?: (rowIdx: number, row: TRow, column: CalculatedColumn<TRow, TSummaryRow>) => void;
@@ -239,3 +240,11 @@ export type ColSpanArgs<R, SR> = {
   type: 'SUMMARY';
   row: SR;
 };
+
+export type RowHeightArgs<R> = {
+  type: 'ROW';
+  row: R;
+} | {
+  type: 'GROUP';
+  row: GroupRow<R>;
+};

stories/demos/Grouping.tsx

@@ -98,13 +98,13 @@ function createRows(): readonly Row[] {
   for (let i = 1; i < 10000; i++) {
     rows.push({
       id: i,
-      year: 2015 + faker.random.number(3),
+      year: 2015 + faker.datatype.number(3),
       country: faker.address.country(),
-      sport: sports[faker.random.number(sports.length - 1)],
+      sport: sports[faker.datatype.number(sports.length - 1)],
       athlete: faker.name.findName(),
-      gold: faker.random.number(5),
-      silver: faker.random.number(5),
-      bronze: faker.random.number(5)
+      gold: faker.datatype.number(5),
+      silver: faker.datatype.number(5),
+      bronze: faker.datatype.number(5)
     });
   }