# Streamgraph

A React component in [Beamline](https://beamline.io/)'s [Charts & data-vis](https://beamline.io/components/charts) category. Live demo: https://beamline.io/components/streamgraph

Stacked flows over time around a centre baseline, with silhouette, wiggle, expand (shares) and zero offsets: a legend that turns layers on and off, a tooltip that follows the pointer or the arrow keys, and hatched periods where a layer was not measured.

## Use it for

- How the mix of categories shifts over time when the overall shape matters more than exact values: tickets by topic, traffic by platform.

## Not for

- Exact values per period ([area-chart](https://beamline.io/components/area-chart) stacked, or [bar-chart](https://beamline.io/components/bar-chart)).
- A few series where each level matters ([line-chart](https://beamline.io/components/line-chart)).

## Anatomy

- title, description, actions (offset switch), legend (toggle buttons), table button
- plot (focusable)
- layers (smooth bands)
- time axis
- share axis (expand only)
- guide line and tooltip at the active period
- hatched band at a period where a layer was not measured

## Variants

- **0**: offset: wiggle (minimises layer slopes) · silhouette (centred) · expand (shares of 100%) · zero (flat baseline)

## States

- loading (skeleton)
- empty
- missing value: the layer thins to nothing there, a hatched band marks the period, tooltip and table say Not measured
- layers hidden from the legend (the rest reflow)
- active period (guide, tooltip; the layer under the pointer leads)
- every layer hidden (a note says so)
- table view
- right-to-left: time still runs left to right

## Keyboard

- Tab focuses the plot (a slider over the periods whose value text reads every layer); ←/→ move the tooltip period by period, Home/End to the ends, Escape hides it
- Legend buttons toggle layers (aria-pressed)
- The table button lists every value

## Motion

Layers grow out of the baseline once; toggling a layer or the offset reflows at once. Nothing moves under reduced motion.

## Props

| Prop | Type | Default | Description |
| --- | --- | --- | --- |
| `data / x` | `T[] / keyof T` | — | Rows in time order and the column naming each period. |
| `series` | `ChartSeries[]` | — | Layers from the bottom of the stack up; colours follow the series palette. |
| `offset` | `"wiggle" \| "silhouette" \| "expand" \| "zero"` | — | Baseline. Default wiggle. |
| `height` | `number` | — | Plot height. Default 260. |
| `xFormat / yFormat` | `(v) => string` | — | Period and value formats (ticks, tooltip, table). |
| `legend` | `boolean` | — | Layer toggles. Default true. |
| `title / hideTitle / description` | `string / boolean / ReactNode` | — | The figure's name (a heading unless hidden) is always its accessible name. |
| `table` | `boolean` | — | Offer “View as table”. Default true. |
| `loading` | `boolean` | — | Skeleton of the chart's shape; keeps the frame's size. |
| `actions` | `ReactNode` | — | Controls beside the legend (range, offset). |
| `className` | `string` | — | Lands on the figure. |
| `classNames` | `ChartClassNames` | — | Frame, tooltip and slice-list parts as applicable to this chart. |
| `style / ref` | `CSSProperties / Ref<HTMLElement>` | — | The native chart figure; layout measurement refs stay internal. |

## Dependencies

`motion`

## Import

```tsx
import { Streamgraph } from "@/components/streamgraph/streamgraph";
```

## Get it

Streamgraph is part of Beamline: 190 React components and screens your coding agent (Claude Code, Codex, Cursor or any MCP client) installs into your app through Beamline's MCP server, as a ready-built package or as plain React source you can change. $49 one payment (regular $200), no subscription, a year of updates, one licence for your whole team. [Get Beamline](https://beamline.io/checkout?pack=complete) · [Connect your agent](https://beamline.io/connect)

## More in Charts & data-vis

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- [Bar chart](https://beamline.io/components/bar-chart): Amounts by category as bars: columns or rows, grouped, stacked or as shares, reference lines, five looks (rounded, cells, trace, isometric, monospace), a…
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