Function transposeNote

transposeNote(
    note: NoteData,
    semitones: number,
    opts?: { spelling?: "flat" | "sharp" },
): NoteData
Transpose a note by a signed number of semitones, keeping its spelling.

The letter moves by the diatonic distance of the conventional interval for that many semitones and the accidental is recomputed for the new letter, so enharmonic identity survives: Ab4 up a major second is Bb4, not A#4, and the operation is an exact inverse of itself. An octave-less note stays octave-less.

A bare semitone count cannot distinguish an augmented fourth from a diminished fifth; pass spelling to override the letter distance when the enharmonic choice matters.
Parameters
- note: NoteData
  The note to transpose.
- semitones: number
  The signed semitone offset.
- Optionalopts: { spelling?: "flat" | "sharp" }
  spelling forces the result onto the sharp or flat side instead of following the source note's letter.
Returns NoteData
The transposed note.
Example
```
import { transposeNote, formatNote, parseNote } from '@libraz/libcantus';
formatNote(transposeNote(parseNote('Ab4'), 2)); // 'Bb4'
formatNote(transposeNote(parseNote('Ab4'), 2, { spelling: 'sharp' })); // 'A#4'
```
- Defined in src/core/pitch/index.ts:517