https://www.flipcode.com/archives/Fast_Point-In-Cylinder_Test.shtml

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function cylTest(pt1, pt2, radius, testpt) {
  let dx, dy, dz; // vector d  from line segment point 1 to point 2
  let pdx, pdy, pdz; // vector pd from point 1 to test point
  let dot, dsq;
  let length_sq = Math.pow(pt1.x - pt2.x, 2) + Math.pow(pt1.y - pt2.y, 2) + Math.pow(pt1.z - pt2.z, 2);
  let radius_sq = Math.pow(radius, 2);
  dx = pt2.x - pt1.x; // translate so pt1 is origin.  Make vector from
  dy = pt2.y - pt1.y; // pt1 to pt2.  Need for this is easily eliminated
  dz = pt2.z - pt1.z;

  pdx = testpt.x - pt1.x; // vector from pt1 to test point.
  pdy = testpt.y - pt1.y;
  pdz = testpt.z - pt1.z;

  // Dot the d and pd vectors to see if point lies behind the
  // cylinder cap at pt1.x, pt1.y, pt1.z
  dot = pdx * dx + pdy * dy + pdz * dz;
  // If dot is less than zero the point is behind the pt1 cap.
  // If greater than the cylinder axis line segment length squared
  // then the point is outside the other end cap at pt2.

  if (dot < 0.0 || dot > length_sq) {
    return -1.0;
  } else {
    // Point lies within the parallel caps, so find
    // distance squared from point to line, using the fact that sin^2 + cos^2 = 1
    // the dot = cos() * |d||pd|, and cross*cross = sin^2 * |d|^2 * |pd|^2
    // Carefull: '*' means mult for scalars and dotproduct for vectors
    // In short, where dist is pt distance to cyl axis:
    // dist = sin( pd to d ) * |pd|
    // distsq = dsq = (1 - cos^2( pd to d)) * |pd|^2
    // dsq = ( 1 - (pd * d)^2 / (|pd|^2 * |d|^2) ) * |pd|^2
    // dsq = pd * pd - dot * dot / lengthsq
    //  where lengthsq is d*d or |d|^2 that is passed into this function

    // distance squared to the cylinder axis:

    dsq = pdx * pdx + pdy * pdy + pdz * pdz - (dot * dot) / length_sq;
    if (dsq > radius_sq) {
      return -1.0;
    } else {
      return dsq; // return distance squared to axis
    }
  }
}