feat: error handling for non-integer values

A TypeError will now be thrown when a non-integer number is used in the dimensions parameter

Author: neefrehman

README.md

@@ -72,7 +72,7 @@ const threeDimensionalStringArray = makeMatrix([2, 6, 5], "value");
 
 ### Pass a callback for dynamic initial values
 
-The `initialValues` parameter also accepts a callback which you can use to dynamically create items for each position in the matrix.
+The `initialValues` parameter also accepts a callback, which you can use to dynamically create items for each position in the matrix.
 
 ```js
 // create a 10x10x10 array, with each point a different random number between one and 10

src/__tests__/callback-initial-values.test.ts

@@ -1,10 +1,10 @@
 import makeMatrix from "../index";
 
 // Test arrays of specific dimensions, with callbacks returning initialised values
-test("length: 1 test - With string initialValues", () => {
+test("length: 1 test - With string callback initialValues", () => {
     expect(makeMatrix([1], () => "string")).toStrictEqual(["string"]);
 });
 
-test("length: 2 test - With string initialValues", () => {
+test("length: 2 test - With math callback initialValues", () => {
     expect(makeMatrix([2], () => 10 - 2)).toStrictEqual([8, 8]);
 });

src/__tests__/non-integer-error.test.ts

@@ -0,0 +1,10 @@
+import makeMatrix from "../index";
+
+// Test the throwing of a TypeError if a non-integer is passed in `dimensions`
+test("Array error test - When non-integer is used", () => {
+    expect(() => makeMatrix([1, 0.2, 3])).toThrow(TypeError);
+});
+
+test("Number error test - When non-integer is used", () => {
+    expect(() => makeMatrix(0.2)).toThrow(TypeError);
+});

src/index.ts

@@ -79,6 +79,10 @@ function makeMatrix<T>(
         needsRecursion = remainingDimensions.length > 0;
     }
 
+    if (!Number.isInteger(currentDimensionLength)) {
+        throw new TypeError(`Dimensions must be integers`);
+    }
+
     // 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(() => {