Function dominantKeyOf

dominantKeyOf(tonic: NoteLike, key: KeyLike): ResolvedKey
The dominant key: the key a fifth above, in the mode this key's third names.

The fifth is measured from the tonic, so a key that is not a plain major or minor answers with the same move: the dominant of G mixolydian is D major and the dominant of D dorian is A minor.
Parameters
- tonic: NoteLike
  The spelled tonic of the key, as a note name, note data, or a Note.
- key: KeyLike
  The key/scale, as a key name, a key/scale, or a Key; its mask decides the mode of the result.
Returns ResolvedKey
The key a fifth above, in the mode this key's third names.
Throws
If the tonic or the mask is malformed, or if the resulting signature falls outside [-12, 12] fifths — the dominant of a key already at +12.
Example
```
import { dominantKeyOf, formatNote, majorKey, parseNote } from '@libraz/libcantus';
formatNote(dominantKeyOf(parseNote('C'), majorKey(0)).tonic); // 'G'
```
- Defined in src/theory/scale/relations.ts:416