FillLayer

import { MapView, ShapeSource, FillLayer } from '@rnmapbox/maps';

const polygon = {
  type: 'Feature',
  geometry: {
    type: 'Polygon',
    coordinates: [[
      [-122.4, 37.8],
      [-122.4, 37.7],
      [-122.5, 37.7],
      [-122.5, 37.8],
      [-122.4, 37.8],
    ]],
  },
};

function Map() {
  return (
    <MapView>
      <ShapeSource id="polygon" shape={polygon}>
        <FillLayer
          id="polygon-fill"
          style={{
            fillColor: '#3bb2d0',
            fillOpacity: 0.5,
            fillOutlineColor: '#088',
          }}
        />
      </ShapeSource>
    </MapView>
  );
}