Function transposeChord

transposeChord(chord: ChordData, semitones: number): ChordData
Transpose a chord by a number of semitones.

The interval template is carried over untouched, so a chord whose intervals were customised keeps them, and a slash bass moves with the root. Enharmonic spelling hints are dropped rather than shifted: the letter a transposed root should take depends on the destination key, which a semitone count does not carry. Pass the result through spellChord to respell it.
Parameters
- chord: ChordData
  The chord to transpose.
- semitones: number
  The signed semitone offset.
Returns ChordData
The transposed chord.
Throws
If semitones is not finite.
Example
```
import { formatChordSymbol, parseChordSymbol, transposeChord } from '@libraz/libcantus';
formatChordSymbol(transposeChord(parseChordSymbol('C/G'), 2)); // 'D/A'
```
- Defined in src/theory/chord/index.ts:479