Fixing logic

src/ArrayExtensions.ts

@@ -21,6 +21,7 @@ declare global {
     pick(): T;
     loop(index: number): T;
     shuffle(): this;
+    scale(name: string, base_note?: number): this;
     rotate(steps: number): this;
     unique(): this;
     in(value: T): boolean;
@@ -344,25 +345,18 @@ export const makeArrayExtensions = (api: UserAPI) => {
   Array.prototype.rand = Array.prototype.random;
 };
 
-Array.prototype.scale = function <T>(this: T[], scaleName: string = "major") {
-
-    const scale = SCALES[scaleName];
-
-    //input protect from unknow scale
-    if (!scale) {
-        throw new Error(`Unknown scale ${scaleName}`);
+Array.prototype.scale = function(scale: string = "major", base_note: number = 0) {
+  /**
+    * Returns a note from an array containing a specific scale.
+    *
+    * @param scale - the scale name (string)
+    * @param base_note - the base note to start at (MIDI note number)
+    *
+    */
+  if (SCALES.hasOwnProperty(scale)) {
+    const selected_scale = SCALES[scale]
+    return this.map((value) => selected_scale[value % selected_scale.length] + base_note);
+  } else {
+    return this.map((value) => value + base_note);
   }
-
-    let result = [];
-
-    for (let j = 0; j < scale.length; j++) {
-
-        for (let i = 0; i < this.length; i++) {
-
-            result.push(this[i] + scale[j]);
-        }
-
-    }
-
-    return result;
 };