const Night = Kapsule({
  props: {
    time: { default: new Date() }
  },

  stateInit: () => ({
    halfGlobe: d3.geoCircle()
      .radius(90),
    geoPath: d3.geoPath()
  }),

  init(svg, state, projection) {
    state.geoPath.projection(projection);

    state.nightPath = svg.append('path')
      .attr('class', 'geo night');
  },

  update(state) {
    state.nightPath.attr('d', state.geoPath(
      state.halfGlobe.center(antipode(solarPosition(state.time)))()
    ));
  }
});