maplibre-gl-js: light position calculation

lightPosition.ts

function lightPosition(lat: number, lng: number) {
  const sin = (d: number) => Math.sin(d * Math.PI / 180);
  const cos = (d: number) => Math.cos(d * Math.PI / 180);
  const acos = (v: number) => Math.acos(v) * 180 / Math.PI;
  const b = acos(cos(lat) * cos(lng));
  const a = acos(sin(lat) / sin(b));
  return [-1, a, b] as [number, number, number];
}