ThemeRiver

A streamgraph — stacked categories flowing over time, each band's thickness its value. x is the time column (ISO dates parse best), y the value, and series the category each stream represents.

<ThemeRiver data={daily_streams} x="date" y="value" series="metric" title="Activity streams" />

From the semantic layer #

Like every chart, ThemeRiver also takes semantic metric refs instead of data={query}. series= is required (it splits the streams), so pair a metric with a by time dimension and a series category:

<ThemeRiver metric={sales.revenue} by={sales.order_date} series={sales.region} grain="month" />

Attributes #

Attribute	Purpose
`data`	Required. The query to plot (`data={query}`).
`x`	Required. Time column (ISO dates like `2026-06-01` parse cleanly).
`y`	Required. Value column — the band thickness.
`series`	Required. Category column — one stream per distinct value.
`title`	Chart title.
`sort_by`	Column to sort by before plotting.
`color`	Single color or comma-separated palette override.
`height`	Pixel height (default `300`).
`col-span`	Columns to span inside a `<Grid>`.
`format` · `currency` · `decimals` · `locale`	Tooltip value formatting.
`empty_message`	Text shown when the query returns no rows.

ThemeRiver reuses the shared x/y/series attributes — series is required (it's what splits the streams). See Charts.