# Preact Adapter

Install TanStack Charts and its Preact peer:

```sh
pnpm add @tanstack/charts preact
```

```tsx
import { defineChart } from '@tanstack/charts'
import { tooltip } from '@tanstack/charts/tooltip'
import { Chart } from '@tanstack/charts/preact'

export function RevenueChart() {
  const definition = useMemo(
    () => defineChart(createRevenueChart(rows), { tooltip }),
    [rows],
  )

  return (
    <Chart
      definition={definition}
      ariaLabel="Revenue by month"
      aspectRatio={16 / 9}
    />
  )
}
```

`className` and `style` target the outer host. Preact owns that host; the
shared runtime owns the SVG, measurement, interaction, and cleanup. The
adapter emits the initial SVG during SSR and adopts it after mount.

## Lifecycle

The component creates one shared adapter controller, prerenders its initial
SVG, mounts it from a layout effect, forwards complete prop updates, and
destroys it on unmount. Keep stable definitions at module scope. Memoize the
complete definition when it captures component values.

## SSR and hydration

Preact server rendering emits the complete `.ts-chart-host`,
`.ts-chart-surface`, and accessible SVG. `initialWidth` controls responsive
server geometry. The generated `useId()` prefix remains stable when the server
and browser render the same tree. Keep definitions, formatters, and
dimensions deterministic.

## Presentation and rendering

`className` and `style: JSX.CSSProperties` apply to the outer host and are not
forwarded to the chart surface. Custom styles are applied after adapter sizing.
The component starts with SVG and can compose marks that use
`canvasChartRenderer`. Use `renderSvg` to replace SVG serialization without
replacing the shared host.

Exports: `Chart`, `ChartCommonProps`, `ChartPresentationProps`, `ChartProps`,
`ChartTooltipBodyRenderContext`, `ChartDefinition`, and `ChartPoint`.

## Tooltip body composition

```tsx
<Chart
  definition={definition}
  ariaLabel="Revenue"
  renderTooltipBody={({ points, defaultBody, pinned, dismiss }) => (
    <div>
      {defaultBody}
      <SeriesDetail points={points} />
      {pinned ? <button onClick={dismiss}>Close</button> : null}
    </div>
  )}
/>
```

The shared host owns focus, placement, portaling, and dismissal. Preact owns
the returned component lifecycle inside the stable tooltip body target.

See the [`Chart` reference](./reference/chart.md), [SSR and hydration](../../guides/ssr-and-hydration.md),
and [Chart Definition API](../../reference/chart-definitions.md).