With Tanstack Virtual

This skill builds on @tanstack/table-core#core, getting-started, and table-state. Virtual is renderer composition over the final Table model, never a tableFeatures slot.

Setup

import { useRef } from 'preact/hooks'
import { useVirtualizer } from '@tanstack/react-virtual' // via preact/compat

const scrollRef = useRef<HTMLDivElement>(null)
const rows = table.getRowModel().rows
const virtualizer = useVirtualizer({
  count: rows.length,
  getScrollElement: () => scrollRef.current,
  estimateSize: () => 36,
  getItemKey: (index) => rows[index].id,
  overscan: 5,
})

Render a spacer of getTotalSize() and position each row from its virtual item's start.

Core Patterns

Apply Table's column sizes

<td style={{ width: cell.column.getSize() }}>
  <table.FlexRender cell={cell} />
</td>

Measure dynamic rows by index

<div key={row.id} data-index={item.index} ref={virtualizer.measureElement}>
  {row.id}
</div>

Common Mistakes

HIGH Looking for a Preact-specific adapter

There is no @tanstack/preact-virtual package. In the standard Preact setup that aliases React to preact/compat, use the maintained React adapter:

import { useVirtualizer } from '@tanstack/react-virtual'

If the application cannot use the compat alias, integrate the Virtualizer class from @tanstack/virtual-core directly. That is a lower-level integration with application-owned lifecycle and subscriptions; do not invent Preact hooks around it.

Source: docs/framework/preact/guide/virtualization.md

HIGH Virtualizing raw data

Wrong:

useVirtualizer({ count: data.length, getScrollElement, estimateSize })

Correct:

const rows = table.getRowModel().rows
useVirtualizer({ count: rows.length, getScrollElement, estimateSize })

Raw data omits Table's current filtering, sorting, expansion, grouping, and pagination.

Source: docs/framework/preact/guide/virtualization.md

HIGH Assuming layout is automatic

Wrong:

virtualizer.getVirtualItems().map((item) => <div>{rows[item.index].id}</div>)

Correct:

virtualizer
  .getVirtualItems()
  .map((item) => (
    <div
      style={{ position: 'absolute', transform: `translateY(${item.start}px)` }}
    >
      {rows[item.index].id}
    </div>
  ))

Virtual computes geometry; application markup and CSS must apply it and supply the scroll container/spacer.

Source: docs/framework/preact/guide/virtualization.md

API Discovery

Inspect node_modules/@tanstack/preact-table/dist/index.d.ts. For rendering APIs, inspect installed node_modules/@tanstack/react-virtual/dist/ when using the standard preact/compat alias, or node_modules/@tanstack/virtual-core/dist/ for a direct integration. There is no maintained Preact-specific Virtual package or Table example; start from the Preact guide and translate the maintained React examples only through the compat setup it describes.