fix: normalizeNote, pitchClassesToPianoChordNotes

src/utilities/MusicFunctions.ts

@@ -1,7 +1,7 @@
 import { PITCH_CLASS_LETTERS } from '../Constants.js';
 import { Note, PitchClass, Scale } from '../types.js';
 import { rearrangeArray } from './GeneralFunctions.js';
-import { enharmonicPitchClass, getPitchClassIndex } from './PureMusicUtils.js';
+import { enharmonicPitchClass, getPitchClassIndex, normalizePitchClass } from './PureMusicUtils.js';
 
 /**
  * Returns an array of notes with a specific octave.
@@ -30,9 +30,12 @@ export function pitchClassesToPianoChordNotes(pitchClasses: Array<PitchClass>, o
 
   return pitchClasses.map((pitchClass, i) => {
     if(i !== 0) {
-      const pcIndex = getPitchClassIndex(pitchClass);
-      const prevPcIndex = getPitchClassIndex(pitchClasses[i - 1]);
-      if((i - 1) >= 0 && pcIndex < prevPcIndex) {
+      const pcIndex = getPitchClassIndex(normalizePitchClass(pitchClass));
+      const prevPcIndex = getPitchClassIndex(normalizePitchClass(pitchClasses[i - 1]));
+      // Checking if the octave needs to be incremented:
+      // We can know it definitely needs to be incremented if the current pitch class is C.
+      // Otherwise, we need to check if the current pitch class pitch class index is smaller than the previous one, as that would indicate that weve passed the B pitch class.
+      if((pcIndex < prevPcIndex && pitchClass[0] !== 'B') || pitchClass[0] === 'C') {
         currentOctave++;
       }
     }

src/utilities/PureMusicUtils.ts

@@ -155,7 +155,14 @@ export function normalizePitchClass(pc: PitchClass): PitchClass {
 
 export function normalizeNote(note: Note): Note {
   const { pitchClass, octave } = noteToObject(note);
-  return `${normalizePitchClass(pitchClass)}${octave}` as Note;
+  const normalizedPitchClass = normalizePitchClass(pitchClass);
+  let octaveDifference = 0;
+  if(pitchClass[0] === 'B' && pitchClass.includes('#' || 'x')) {
+    octaveDifference = 1;
+  } else if(pitchClass[0] === 'C' && pitchClass.includes('b')) {
+    octaveDifference = -1;
+  }
+  return `${normalizedPitchClass}${octave + octaveDifference}` as Note;
 }
 
 /**

test/utilities/music-functions.spec.js

@@ -79,6 +79,13 @@ describe('Music addon functions', () => {
 
         expect(pitchClassesToPianoChordNotes(bigChord, 3)).to.eql(stub);
       });
+
+      it('with a scale', () => {
+        const bigChord = spellScale(intervalsToNotes('E', [0, 3, 4, 6, 8, 9, 11]));
+        const stub    = ['E3', 'Fx3', 'G#3', 'A#3', 'B#3', 'C#4', 'D#4'];
+
+        expect(pitchClassesToPianoChordNotes(bigChord, 3)).to.eql(stub);
+      });
     });
 
     it('should invert chords when called with inversion value', () => {

test/utilities/pure-music-utils.spec.js

@@ -1,5 +1,5 @@
 import {
-  enharmonicPitchClass, getNotesInterval, getPatternFromNotes, getPatternFromPitchClasses, isPitchClass, isNote, normalizePitchClass, toFlat,
+  enharmonicPitchClass, getNotesInterval, getPatternFromNotes, getPatternFromPitchClasses, isPitchClass, isNote, normalizePitchClass, toFlat, normalizeNote,
 } from '../../lib/index.js';
 
 describe('#PureMusicUtils', () => {
@@ -101,6 +101,16 @@ describe('#PureMusicUtils', () => {
     });
   });
 
+  describe('#normalizeNote', () => {
+    it('should normalize a note', () => {
+      expect(normalizeNote('C#3')).to.equal('C#3');
+      expect(normalizeNote('Gx3')).to.equal('A3');
+      expect(normalizeNote('B#3')).to.equal('C4');
+      expect(normalizeNote('Ab3')).to.equal('Ab3');
+      expect(normalizeNote('Bbb4')).to.equal('A4');
+      expect(normalizeNote('Cbb3')).to.equal('Bb2');
+    });
+  });
   describe('#toFlat', () => {
     it('should turn sharp pitch classes flat', () => {
       expect(toFlat('C#')).to.equal('Db');