IsPointInRange.js

function radiansToDegrees (radians) {
  return radians * (180 / Math.PI)
}

function angleToPoint (p, otherPoint) {
  const angleRadians = Math.atan2(otherPoint.y - p.y, otherPoint.x - p.x)
  return radiansToDegrees(angleRadians)
}

function scenario1 (anglePrev, angleNext, currentPBearing) {
  return anglePrev < currentPBearing && currentPBearing < angleNext
}

function scenario2 (anglePrev, angleNext, currentPBearing) {
  return currentPBearing > anglePrev || currentPBearing < angleNext
}

const anglePrev = angleToPoint(centerPoint, prevPoint)
const angleNext = angleToPoint(centerPoint, nextPoint)
const angleToTestPoint = angleToPoint(centerPoint, pointToTest)

const requiredCalculation = anglePrev < angleNext ? scenario1 : scenario2

const isInRange = requiredCalculation(anglePrev, angleNext, angleToTestPoint)