Storing the seam length to use in another part

Often when designing patterns, we need to true a seam which means to make sure that two parts that need to be joined together are the same distance.

The example below is from Aaron and stores the length of the armhole seam:

// Store length of armhole and neck opening
  new Path()
    .curve(points.armholeCp2, points.strapRightCp1, points.strapRight)
// Seam length is now available in other parts via: