code: function getNormalizeRotations(start, end) {
    // normalize both rotations
    var normStart = normalizeRotation(start)
    var normEnd = normalizeRotation(end)
    // find the shortest arc for each rotation
    Object.keys(start).forEach(function(axis) {
      if (normEnd[axis] - normStart[axis] > 180) normEnd[axis] -= 360
    })
    return { start: normStart, end: normEnd }
  }
docs: we want to prevent excessive spinning in rotations