Colors via function

Instead of passing `keyToColor` you can pass a function `keyToColorFn`.

You also have to pass `key` or `key_alt` (see basic props for an examplation of these)

Note that if you pass both `keyToColor` and `keyToColorFn`, `keyToColor` takes precedence.

Also note that if the value returned by `keyToColorFn` is falsy the fallback is `defaultFill` (which defaults to `white`).

Usage

<ChoroplethG
  {height}
  {keyToColorFn}
  {width}
  key='iso_a2'
  topojson={world_110m_iso_a2}
  topojsonId='countries'
/>

"iso_a2"

▶ ƒ scale(d)

length: 1
name: "scale"
prototype: { constructor: ƒ }
[[Function]]: function scale(d) { let i = index.get(d); if (i === undefined) { if (unknown !== implicit) return unknown; index.set(d, i = domain.push(d) - 1); } return range[i % range.length]; }
[[Prototype]]: ƒ ()

▶ { type: "Topology" ,objects: {…} ,arcs: Array(595) ,bbox: Array(4) ,transform: {…} }

"countries"