Merge pull request #27 from kilmc/add-parallel-modes

[feat] Add parallel modes
kilmc · Nov 4, 2023 · 6caf579 · 6caf579
2 parents 9a1fa7e + 0a2b410
commit 6caf579
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diff --git a/.changeset/strange-squids-pretend.md b/.changeset/strange-squids-pretend.md
@@ -0,0 +1,5 @@
+---
+"@kilmc/music-fns": minor
+---
+
+Add parallel modes to key
diff --git a/src/public/getKey/getKey.test.ts b/src/public/getKey/getKey.test.ts
@@ -100,4 +100,68 @@ describe('makeKey', () => {
       expect(chordNumeralsResult).toStrictEqual(chordNumerals);
     }
   );
+
+  it('gets relative modes', () => {
+    expect(getKey('C major')?.relativeModes).toStrictEqual([
+      'C major',
+      'D dorian',
+      'E phrygian',
+      'F lydian',
+      'G mixolydian',
+      'A minor',
+      'B locrian',
+    ]);
+
+    expect(getKey('C melodic minor')?.relativeModes).toStrictEqual([
+      'C melodic minor',
+      'D dorian flat 2',
+      'Eb lydian augmented',
+      'F lydian dominant',
+      'G mixolydian flat 6',
+      'A aeolian flat 2',
+      'B super locrian',
+    ]);
+
+    expect(getKey('C melodic minor')?.relativeModes).toStrictEqual([
+      'C melodic minor',
+      'D dorian flat 2',
+      'Eb lydian augmented',
+      'F lydian dominant',
+      'G mixolydian flat 6',
+      'A aeolian flat 2',
+      'B super locrian',
+    ]);
+  });
+
+  it('gets parallel modes', () => {
+    expect(getKey('C major')?.parallelModes).toStrictEqual([
+      'C major',
+      'C dorian',
+      'C phrygian',
+      'C lydian',
+      'C mixolydian',
+      'C minor',
+      'C locrian',
+    ]);
+
+    expect(getKey('C melodic minor')?.parallelModes).toStrictEqual([
+      'C melodic minor',
+      'C dorian flat 2',
+      'C lydian augmented',
+      'C lydian dominant',
+      'C mixolydian flat 6',
+      'C aeolian flat 2',
+      'C super locrian',
+    ]);
+
+    expect(getKey('C melodic minor')?.parallelModes).toStrictEqual([
+      'C melodic minor',
+      'C dorian flat 2',
+      'C lydian augmented',
+      'C lydian dominant',
+      'C mixolydian flat 6',
+      'C aeolian flat 2',
+      'C super locrian',
+    ]);
+  });
 });
diff --git a/src/public/getKey/getKey.ts b/src/public/getKey/getKey.ts
@@ -2,6 +2,7 @@ import { ModeRoot } from '../../consts/keys.js';
 import { Note } from '../../consts/notes.js';
 import { ScaleType } from '../../consts/scales.js';
 import { Chord } from '../getChord/getChord.js';
+import { getParallelModeNames } from '../getScale/getParallelModeNames.js';
 import { getRelativeModeNames } from '../getScale/getRelativeModeNames.js';
 import { getScale } from '../getScale/getScale.js';
 import { getKeyChords } from './getKeyChords.js';
@@ -13,6 +14,7 @@ export type Key = {
   notes: Note[];
   chords: Chord[];
   relativeModes?: string[];
+  parallelModes?: string[];
   modeOf?: ModeRoot;
 };
 
@@ -24,6 +26,7 @@ export const getKey = (input: string): Key | undefined => {
   if (chords === undefined) return undefined;
 
   const relativeModes = getRelativeModeNames(scale);
+  const parallelModes = getParallelModeNames(scale);
 
   return {
     name: scale.name,
@@ -33,5 +36,6 @@ export const getKey = (input: string): Key | undefined => {
     chords: chords,
     modeOf: scale.modeOf,
     relativeModes,
+    parallelModes,
   };
 };
diff --git a/src/public/getScale/getParallelModeNames.ts b/src/public/getScale/getParallelModeNames.ts
@@ -0,0 +1,10 @@
+import { modalScaleDefinitions } from '../../consts/scales.js';
+import { Scale } from './getScale.js';
+
+export const getParallelModeNames = (scale: Scale) => {
+  if (scale.modeOf === undefined) return undefined;
+
+  return modalScaleDefinitions[scale.modeOf].map(
+    (mode) => `${scale.root} ${mode.name}`
+  );
+};