EnsembleGhosts

EnsembleGhosts draws a faint bundle of member paths with one emphasized representative, so you can see where the simulated futures disagree in shape and not only at the endpoint. Two ensembles can share an average and a final range while running completely different routes to get there, which is what a mean line hides. The emphasized path defaults to the real member closest to the pointwise median, so the representative is a path the simulation produced; emphasis="median" draws the synthetic pointwise median instead. Ghost selection is evenly spaced endpoint-rank quantiles, so the same input renders identically every time.

Install

import { EnsembleGhosts } from "@microcharts/react/ensemble-ghosts";// futures — real values under “Sample data” below<EnsembleGhosts data={futures} title="Simulated futures" />

// 24 simulated futures — a fan of walks with diverse shapesconst futures = Array.from({ length: 24 }, (_m, i) =>  Array.from({ length: 10 }, (_, t) =>    Math.round(40 + (i - 12) * 0.55 * t * 0.4 + 3 * Math.sin(i + t) + t * 0.5),  ),);

Try it

When to use it

Use it for a KPI card that shows the futures rather than the average, for Monte-Carlo and simulation output where paths disagree in shape, and for showing that outcomes fan out. When you need interval precision, use ForecastCone; for a single path, use Sparkline.

Sizing

Variants

endpoints marks where each ghost lands. label="end" is the default and states the emphasized path's landing value in a right gutter; label="none" drops it.

Edge cases

With one member there is no bundle to draw, so the chart renders that single path as the representative and the summary states its ending value rather than a spread. A member containing a non-finite value (NaN, Infinity) is excluded from ghost selection and from the median entirely, rather than gapped mid-path, and a dev-only console warning flags it: a partially invalid future usually means bad simulation output.

Four homes

Accessibility

The accessible name states the endpoint spread and the typical path: "5 simulated paths end between 28 and 61; typical path ends near 50." The static frame is not a hypothetical-outcome plot. The HOP loop, which flips through the members one at a time on hover, lives only in the interactive entry; with reduced motion, ←/→ step the members discretely instead, and each one is announced with its endpoint.

The interactive entry follows the shared interaction contract: arrow keys rove between units on both axes, Home and End jump to the ends, and a click, tap, Enter or Space selects a unit — pinning its readout so it survives blur, until you select it again or press Escape. On touch, a tap pins and a drag scrubs.

Props

Plus the shared grammar — data, domain, color, title, summary, format — and the layout props (width, height, className, style) that every chart accepts. Interactive entries also share animate and live, and — wherever a chart has more than one navigable unit — onActive, onSelect, selectedIndex and defaultSelectedIndex; and — wherever the chart shows a hover value — readout. See the shared grammar.