perf: move mapping of initialValues to final recursive function call

The mapping of intialValues into the matrix now will only occur in the final recursive call of
makeMatrix instead of at all calls. This should help with performance, especially when a callback is
used to intialise values across ther matrix.

Author: neefrehman

src/index.ts

@@ -85,17 +85,17 @@ function makeMatrix<T>(
 
     // Spread operator used as as constructed array's can't be mapped:
     // https://itnext.io/heres-why-mapping-a-constructed-array-doesn-t-work-in-javascript-f1195138615a
-    const currentMatrix = [...Array(currentDimensionLength)].map(() => {
-        return typeof initialValues === "function"
-            ? initialValues()
-            : initialValues;
-    });
+    const currentMatrix = [...Array(currentDimensionLength)];
 
     const finalMatrix = needsRecursion
         ? currentMatrix.map(() =>
               makeMatrix(remainingDimensions, initialValues)
           )
-        : currentMatrix;
+        : currentMatrix.map(() => {
+              return typeof initialValues === "function"
+                  ? initialValues()
+                  : initialValues;
+          });
 
     return finalMatrix;
 }