function findClosestPointIndexWithinRadius(points, x, y, radiusThreshold) {
    let closestIdx;
    let closestDist = Number.MAX_VALUE;
    points.forEach((d, idx) => {
      let distSqrd = Math.pow(d.x - x, 2) + Math.pow(d.y - y, 2); // changeto: (d.x - x)**2 + (d.y - y)**2;
      if (distSqrd < closestDist && distSqrd < radiusThreshold) {
        closestIdx = idx;
        closestDist = distSqrd;
      }
    });
    return closestIdx;
  }
/**
   * Find the index of the closest coordinate to a
   * reference coordinate in an array of coordinates.
   * If no point is found within the threshold distance
   * undefined is returned.
   */
Find the index of the closest coordinate to a
reference coordinate in an array of coordinates.
If no point is found within the threshold distance
undefined is returned.
Find the index of the closest coordinate to a reference coordinate in an array of coordinates . If no point is found within the threshold distance undefined is returned .
function findClosestPointIndexWithinRadius(points, x, y, radiusThreshold) {
    let closestIdx;
    let closestDist = Number.MAX_VALUE;
    points.forEach((d, idx) => {
      let distSqrd = Math.pow(d.x - x, 2) + Math.pow(d.y - y, 2); 
      if (distSqrd < closestDist && distSqrd < radiusThreshold) {
        closestIdx = idx;
        closestDist = distSqrd;
      }
    });
    return closestIdx;
  }
function findClosestPointIndexWithinRadius ( points , x , y , radiusThreshold ) { let closestIdx ; let closestDist = Number . MAX_VALUE ; points . forEach ( ( d , idx ) => { let distSqrd = Math . pow ( d . x - x , 2 ) + Math . pow ( d . y - y , 2 ) ; if ( distSqrd < closestDist && distSqrd < radiusThreshold ) { closestIdx = idx ; closestDist = distSqrd ; } } ) ; return closestIdx ; }
Find the index of the closest coordinate to a
 reference coordinate in an array of coordinates.
Find the index of the closest coordinate to a reference coordinate in an array of coordinates .
// changeto: (d.x - x)**2 + (d.y - y)**2;