f = new api.Fretboard();
Add a Shape corresponding to the C major scale:
s = f.addShape('8 10, 7 8 10, 7 9 10, 7 9 10, 8 10, 7 8');
Transpose this shape down one string, which gives us the F major scale:
s.transposeByStrings(1);
Transpose this shape up one string, to get back to the C major scale:
s.transposeByStrings(-1);