React Example: Virtualized Rows Experimental

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import React from 'react'
import ReactDOM from 'react-dom/client'
import {
  FlexRender,
  columnSizingFeature,
  createColumnHelper,
  createSortedRowModel,
  rowSortingFeature,
  sortFns,
  useTable,
} from '@tanstack/react-table'
import { useVirtualizer } from '@tanstack/react-virtual'
import { makeData } from './makeData'
import type { ReactTable, Row } from '@tanstack/react-table'
import type { Virtualizer } from '@tanstack/react-virtual'
import type { Person } from './makeData'
import './index.css'

const features = {
  columnSizingFeature,
  rowSortingFeature,
  sortedRowModel: createSortedRowModel(),
  sortFns,
}

const columnHelper = createColumnHelper<typeof features, Person>()
// This is a dynamic row height example, which is more complicated, but allows for a more realistic table.
// See https://tanstack.com/virtual/v3/docs/examples/react/table for a simpler fixed row height example.
function App() {
  const columns = React.useMemo(
    () =>
      columnHelper.columns([
        columnHelper.accessor('id', {
          header: 'ID',
          size: 60,
        }),
        columnHelper.accessor('firstName', {
          cell: (info) => info.getValue(),
        }),
        columnHelper.accessor((row) => row.lastName, {
          id: 'lastName',
          cell: (info) => info.getValue(),
          header: () => <span>Last Name</span>,
        }),
        columnHelper.accessor('age', {
          header: () => 'Age',
          size: 50,
        }),
        columnHelper.accessor('visits', {
          header: () => <span>Visits</span>,
          size: 50,
        }),
        columnHelper.accessor('status', {
          header: 'Status',
        }),
        columnHelper.accessor('progress', {
          header: 'Profile Progress',
          size: 80,
        }),
        columnHelper.accessor('createdAt', {
          header: 'Created At',
          cell: (info) => info.getValue<Date>().toLocaleString(),
          size: 250,
        }),
      ]),
    [],
  )

  const [data, setData] = React.useState(() => makeData(50_000))
  const refreshData = () => setData(makeData(50_000))
  const stressTest = () => setData(makeData(500_000))

  const table = useTable(
    {
      features,
      columns,
      data,
      debugTable: true,
    },
    (state) => state, // default selector
  )

  // The virtualizer needs to know the scrollable container element
  const tableContainerRef = React.useRef<HTMLDivElement>(null)

  // All important CSS styles are included as inline styles for this example. This is not recommended for your code.
  return (
    <div className="app">
      {process.env.NODE_ENV === 'development' ? (
        <p>
          <strong>Notice:</strong> You are currently running React in
          development mode. Virtualized rendering performance will be slightly
          degraded until this application is built for production.
        </p>
      ) : null}
      <div>
        <button onClick={refreshData}>Regenerate Data</button>
        <button onClick={stressTest}>Stress Test (500k rows)</button>
      </div>
      ({data.length.toLocaleString()} rows)
      <div
        className="container"
        ref={tableContainerRef}
        style={{
          overflow: 'auto', // our scrollable table container
          position: 'relative', // needed for sticky header
          height: '800px', // should be a fixed height
        }}
      >
        {/* Even though we're still using sematic table tags, we must use CSS grid and flexbox for dynamic row heights */}
        <table style={{ display: 'grid' }}>
          <thead
            style={{
              display: 'grid',
              height: '34px',
              position: 'sticky',
              top: 0,
              zIndex: 1,
            }}
          >
            {table.getHeaderGroups().map((headerGroup) => (
              <tr
                key={headerGroup.id}
                style={{ display: 'flex', height: '34px', width: '100%' }}
              >
                {headerGroup.headers.map((header) => {
                  return (
                    <th
                      key={header.id}
                      style={{
                        alignItems: 'center',
                        display: 'flex',
                        height: '34px',
                        width: header.getSize(),
                      }}
                    >
                      <div
                        className={
                          header.column.getCanSort() ? 'sortable-header' : ''
                        }
                        onClick={header.column.getToggleSortingHandler()}
                        title={
                          header.column.getCanSort()
                            ? header.column.getNextSortingOrder() === 'asc'
                              ? 'Sort ascending'
                              : header.column.getNextSortingOrder() === 'desc'
                                ? 'Sort descending'
                                : 'Clear sort'
                            : undefined
                        }
                      >
                        <FlexRender header={header} />
                        {{
                          asc: ' 🔼',
                          desc: ' 🔽',
                        }[header.column.getIsSorted() as string] ?? null}
                      </div>
                    </th>
                  )
                })}
              </tr>
            ))}
          </thead>
          <TableBodyWrapper
            table={table}
            tableContainerRef={tableContainerRef}
          />
        </table>
      </div>
    </div>
  )
}

interface TableBodyWrapperProps {
  table: ReactTable<typeof features, Person>
  tableContainerRef: React.RefObject<HTMLDivElement | null>
}

function TableBodyWrapper({ table, tableContainerRef }: TableBodyWrapperProps) {
  const rowRefsMap = React.useRef<Map<number, HTMLTableRowElement>>(new Map())

  const { rows } = table.getRowModel()

  const rowVirtualizer = useVirtualizer<HTMLDivElement, HTMLTableRowElement>({
    count: rows.length,
    estimateSize: () => 33, // estimate row height for accurate scrollbar dragging
    getScrollElement: () => tableContainerRef.current,
    // measure dynamic row height, except in firefox because it measures table border height incorrectly
    measureElement:
      typeof window !== 'undefined' &&
      navigator.userAgent.indexOf('Firefox') === -1
        ? (element) => element.getBoundingClientRect().height
        : undefined,
    overscan: 5,
    onChange: (instance) => {
      // requestAnimationFrame(() => {
      instance.getVirtualItems().forEach((virtualRow) => {
        const rowRef = rowRefsMap.current.get(virtualRow.index)
        if (!rowRef) return
        rowRef.style.transform = `translateY(${virtualRow.start}px)`
      })
      // })
    },
  })

  React.useLayoutEffect(() => {
    rowVirtualizer.measure()
  }, [table.state])

  return (
    <TableBody
      rowRefsMap={rowRefsMap}
      rowVirtualizer={rowVirtualizer}
      table={table}
    />
  )
}

interface TableBodyProps {
  table: ReactTable<typeof features, Person>
  rowVirtualizer: Virtualizer<HTMLDivElement, HTMLTableRowElement>
  rowRefsMap: React.MutableRefObject<Map<number, HTMLTableRowElement>>
}

function TableBody({ rowVirtualizer, table, rowRefsMap }: TableBodyProps) {
  const { rows } = table.getRowModel()
  const virtualRowIndexes = rowVirtualizer.getVirtualIndexes()

  return (
    <tbody
      style={{
        display: 'grid',
        height: `${rowVirtualizer.getTotalSize()}px`, // tells scrollbar how big the table is
        position: 'relative', // needed for absolute positioning of rows
      }}
    >
      {virtualRowIndexes.map((virtualRowIndex) => {
        const row = rows[virtualRowIndex]
        return (
          <TableBodyRowMemo
            key={row.id}
            row={row}
            rowRefsMap={rowRefsMap}
            rowVirtualizer={rowVirtualizer}
            virtualRowIndex={virtualRowIndex}
          />
        )
      })}
    </tbody>
  )
}

interface TableBodyRowProps {
  row: Row<typeof features, Person>
  rowRefsMap: React.MutableRefObject<Map<number, HTMLTableRowElement>>
  rowVirtualizer: Virtualizer<HTMLDivElement, HTMLTableRowElement>
  virtualRowIndex: number
}

function TableBodyRow({
  row,
  rowRefsMap,
  rowVirtualizer,
  virtualRowIndex,
}: TableBodyRowProps) {
  return (
    <tr
      data-index={virtualRowIndex} // needed for dynamic row height measurement
      ref={(node) => {
        if (node && typeof virtualRowIndex !== 'undefined') {
          rowVirtualizer.measureElement(node) // measure dynamic row height
          rowRefsMap.current.set(virtualRowIndex, node) // store ref for virtualizer to apply scrolling transforms
        }
      }}
      key={row.id}
      style={{
        display: 'flex',
        position: 'absolute',
        width: '100%',
      }}
    >
      {row.getAllCells().map((cell) => {
        return (
          <td
            key={cell.id}
            style={{
              display: 'flex',
              width: cell.column.getSize(),
            }}
          >
            <FlexRender cell={cell} />
          </td>
        )
      })}
    </tr>
  )
}

// test out when rows don't re-render at all (future TanStack Virtual release can make this unnecessary)
const TableBodyRowMemo = React.memo(
  TableBodyRow,
  (_prev, next) => next.rowVirtualizer.isScrolling,
) as typeof TableBodyRow

const rootElement = document.getElementById('root')

if (!rootElement) throw new Error('Failed to find the root element')

ReactDOM.createRoot(rootElement).render(
  // <React.StrictMode>
  <App />,
  // </React.StrictMode>,
)