# Svelte Chart

```svelte
<script lang="ts">
  import { Chart } from '@tanstack/svelte-charts'
</script>
```

The definition infers datum and coordinate types for every callback. Replace
its identity when captured application values change.
It also owns `focus`, `focusRing`, `cursor`, `tooltip`, `animate`, `keyboard`,
`maxFocusDistance`, and `spatialIndex`.

## Props

| Prop                 | Type                                         | Default               | Meaning                                                |
| -------------------- | -------------------------------------------- | --------------------- | ------------------------------------------------------ |
| `definition`         | `ChartDefinition`                            | Required              | Framework-neutral chart definition                     |
| `ariaLabel`          | `string`                                     | Required              | Accessible chart name                                  |
| `ariaDescription`    | `string`                                     | None                  | Optional accessible description                        |
| `height`             | `number`                                     | `320` without a ratio | Fixed CSS and scene height                             |
| `aspectRatio`        | `number`                                     | None                  | Positive width-to-height ratio when height is absent   |
| `width`              | `number`                                     | Responsive            | Fixed CSS and scene width                              |
| `initialWidth`       | `number`                                     | `640`                 | Initial and server width before responsive measurement |
| `tabIndex`           | `number`                                     | `0`                   | Surface tab index; `keyboard: false` forces `-1`       |
| `idPrefix`           | `string`                                     | Generated             | Prefix for renderer-owned document IDs                 |
| `renderSvg`          | `ChartSvgRenderer<TDatum, TXValue, TYValue>` | `renderChartSvg`      | Scene-to-SVG renderer                                  |
| `measureText`        | `ChartTextMeasurer`                          | Host measurer         | Guide text measurement                                 |
| `onFocusChange`      | `(point: ChartPoint \| null) => void`        | None                  | Primary focus callback                                 |
| `onFocusGroupChange` | `(points: readonly ChartPoint[]) => void`    | None                  | Grouped focus callback                                 |
| `onSelect`           | `(point: ChartPoint \| null) => void`        | None                  | Pointer or keyboard activation callback                |
| `onRender`           | `(context: ChartRenderContext) => void`      | None                  | Live SVG, container, and scene after rendering         |
| `tooltipBody`        | `Snippet<[ChartTooltipBodySnippetContext]>`  | None                  | Composes Svelte content inside the native tooltip body |
| `class`              | `string`                                     | None                  | Extra class on the outer `.ts-chart-host`              |
| `style`              | `string`                                     | None                  | Outer host declarations applied after adapter sizing   |
| `className`          | `string`                                     | None                  | Extra class on the rendered SVG surface                |

Interaction hooks are Svelte 5 callback props. They are not component events.

```svelte
{#snippet tooltipBody({ points, defaultBody, pinned, dismiss })}
  {@render defaultBody()}
  <SeriesDetail {points} />
  {#if pinned}<button onclick={dismiss}>Close</button>{/if}
{/snippet}

<Chart {definition} ariaLabel="Revenue" {tooltipBody} />
```

The snippet context also includes `content`. Ordering, anchoring, placement,
portaling, and pinning remain in the definition.

## Exported types

`ChartCommonProps` contains the common host and presentation props.
`ChartProps` adds the definition. `ChartPresentationProps` contains `class`
and the string `style`. `ChartTooltipBodySnippetContext` describes the snippet
argument. The package also re-exports `ChartDefinition` and `ChartPoint`.

See the [Svelte adapter](../adapter.md) for lifecycle and SSR behavior,
[Focus and interaction](../../../reference/focus-and-interaction.md) for
callback semantics, and [Rendering and export](../../../reference/rendering-and-export.md)
for custom SVG renderers.