Circumcircle from three points

circumcircle.js

function circumcircle(point0, point1, point2) {
  const x1 = point1.x - point0.x;
  const y1 = point1.y - point0.y;
  const x2 = point2.x - point0.x;
  const y2 = point2.y - point0.y;
  const k = 2 * (x1 * y2 - y1 * x2);

  if (k === 0) {
    return null;
  }

  const a = (point1.x + point0.x) * x1 + (point1.y + point0.y) * y1;
  const b = (point2.x + point0.x) * x2 + (point2.y + point0.y) * y2;
  const x = (a * y2 - b * y1) / k;
  const y = (b * x1 - a * x2) / k;
  const radius = Math.sqrt((point0.x - x) * (point0.x - x) + (point0.y - y) * (point0.y - y));

  return {x, y, radius};
}