Function geometryFamily

geometryFamily(kind: unknown): "line" | "polygon" | "point" | null
The single family a declared kind names: point, line or polygon.

For a reader that draws ONE thing per layer — a legend symbol — and so needs the family rather than the encodings. Both vocabularies are read: multipolygon, fill-extrusion and MultiPolygon are all polygons.

null for a kind that names no single family — mixed, which a vector-tile layer may declare, or a token nobody defined. The caller owns what that means for it; a guess here would be indistinguishable from a declaration.
Parameters
- kind: unknown
  One declared value, in either vocabulary.
Returns "line" | "polygon" | "point" | null
The family, or null.
Example
```
geometryFamily("multipolygon");  // "polygon"
geometryFamily("LineString");    // "line"
geometryFamily("mixed");         // null
```
- Defined in packages/core/src/kernel/config/layer-geometry.ts:131