# XWUIChartFanChart

A fan chart: a fixed-type (`fanChart`) wrapper around `XWUIChart` that projects a central path with
progressively widening prediction intervals, so forecast uncertainty visibly "fans out" the further
ahead you look. Pass `series` of `{ name, data: [{ x, y }] }` plus an optional `block` preset (1-4)
and `size` (`sm` / `md` / `lg`); the shared block config also exposes legend, grid, axis,
and tooltip-formatter toggles. Use it for projections where the plausible range grows over the
horizon, such as economic or population forecasts.

## Basic Usage

Two named series of monthly values drawn as a central path with widening confidence fan at the
md size preset.

```example
file: examples/BasicUsage.ts
html: examples/BasicUsage.html
title: Basic Usage
description: Two monthly series rendered as fan-chart projections with widening intervals.
```

## GDP Growth Projection Fan

P10, P50, and P90 GDP-growth paths from 2025 to 2032 whose spread widens each year, fanning out the
forecast uncertainty over the horizon.

```example
file: examples/GdpGrowthProjectionFan.ts
html: examples/GdpGrowthProjectionFan.html
title: GDP Growth Projection Fan
description: Percentile GDP-growth paths whose interval widens further into the forecast.
```

## Portfolio Value Projection

A $100k portfolio projected along Pessimistic, Median, and Optimistic paths over ten years, with a
dollar value formatter on the grid.

```example
file: examples/PortfolioValueProjection.ts
html: examples/PortfolioValueProjection.html
title: Portfolio Value Projection
description: Three portfolio-growth scenarios fanning out with a $ value formatter.
```

```api
```