fix mtsBytesToHex style and tests

xenharmonic-devs · Nov 16, 2023 · 10532a4 · 10532a4
1 parent b64b7c0
commit 10532a4
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Showing 2 changed files with 10 additions and 7 deletions.
diff --git a/src/__tests__/conversion.spec.ts b/src/__tests__/conversion.spec.ts
@@ -219,9 +219,12 @@ describe('MTS data hex string converter', () => {
     expect(mtsBytesToHex(new Uint8Array([69, 0, 0]))).toEqual('450000');
     expect(mtsBytesToHex(new Uint8Array([69, 10, 6]))).toEqual('450a06');
   });
-  it('masks int values above 0x7f by 0x7f', () => {
-    expect(mtsBytesToHex(new Uint8Array([69, 240, 6]))).toEqual('457006');
-    expect(mtsBytesToHex(new Uint8Array([69, 255, 6]))).toEqual('457f06');
+  it('clamps int values above 0x7f to 0x7f', () => {
+    expect(mtsBytesToHex(new Uint8Array([69, 240, 6]))).toEqual('457f06');
+    expect(mtsBytesToHex(new Uint8Array([128, 255, 128]))).toEqual('7f7f7f');
+  });
+  it('allow value reserved for "no tuning change"', () => {
+    expect(mtsBytesToHex(new Uint8Array([127, 127, 127]))).toEqual('7f7f7f');
   });
 });
 

diff --git a/src/conversion.ts b/src/conversion.ts
@@ -118,7 +118,7 @@ export function mtsBytesToMts(mtsBytes: Uint8Array): number {
   let lsb = mtsBytes[2];
 
   const noteNumber = mtsBytes[0] > 0x7f ? 0x7f : mtsBytes[0];
-  if (noteNumber == 0x7f) {
+  if (noteNumber === 0x7f) {
     if (lsb >= 0x7f) lsb = 0x7e;
   } else if (lsb > 0x7f) lsb = 0x7f;
 
@@ -147,9 +147,9 @@ export function mtsBytesToHex(mtsBytes: Uint8Array): String {
   const msb = mtsBytes[1] > 0x7f ? 0x7f : mtsBytes[1];
   const lsb = mtsBytes[2] > 0x7f ? 0x7f : mtsBytes[2];
   return (
-    (noteNumber).toString(16).padStart(2, '0') +
-    (msb).toString(16).padStart(2, '0') +
-    (lsb).toString(16).padStart(2, '0')
+    noteNumber.toString(16).padStart(2, '0') +
+    msb.toString(16).padStart(2, '0') +
+    lsb.toString(16).padStart(2, '0')
   );
 }