module.exports = function deg2rad(angle) {
  //  discuss at: https://locutus.io/php/deg2rad/
  // original by: Enrique Gonzalez
  // improved by: Thomas Grainger (https://graingert.co.uk)
  //   example 1: deg2rad(45)
  //   returns 1: 0.7853981633974483

  return angle * 0.017453292519943295 // (angle / 180) * Math.PI;
}