musical transposition in javascript

I'm trying to make a transposer in JavaScript..
Give it a key and a scale/mode and it will generate it for you
For instance
C Lydian (WWWHWWH) is C D E F# G A B
C Aeolian (WHWWHWW) is C D Eb F G Ab Bb
I cannot for the life of me figure out how to accomplish this.
Thoughts?
>inb4 SICP

>>11
Again, inelegant
That would require an exception for nearly every scale
I might as well hard-code every scale and just parse that
I should only need two arrays, a list of keys 0-12 (C, C#/Db, etc) the name and formula of every scale
Every thing else should be generated by code