Last fix I hope

src/ArrayExtensions.ts

@@ -359,7 +359,7 @@ Array.prototype.scale = function (
 
   // This is a helper function to handle up or down octaviation.
   const mod = (n: number, m: number) => ((n % m) + m) % m;
-  const selected_scale = stepsToScale(safeScale[scale]);
+  const selected_scale = stepsToScale(safeScale(scale));
   return this.map((value) => {
     const octaveShift = Math.floor(value / selected_scale.length) * 12;
     return (
@@ -380,7 +380,7 @@ Array.prototype.scaleArp = function (
    *
    * @returns arpeggiated notes from the scale
    */
-  const scale = stepsToScale(safeScale[scaleName]);
+  const scale = stepsToScale(safeScale(scaleName));
 
   let result = [];