fix: cleanup CheckKishnamurthyNumber

Maths/CheckKishnamurthyNumber.js

@@ -24,7 +24,10 @@ const factorial = (n) => {
 const CheckKishnamurthyNumber = (number) => {
   // firstly, check that input is a number or not.
   if (typeof number !== 'number') {
-    return new TypeError('Argument is not a number.')
+    throw new TypeError('Argument is not a number.')
+  }
+  if (number === 0) {
+    return false
   }
   // create a variable to store the sum of all digits factorial.
   let sumOfAllDigitFactorial = 0

Maths/test/CheckKishnamurthyNumber.test.js

@@ -0,0 +1,18 @@
+import { CheckKishnamurthyNumber } from '../CheckKishnamurthyNumber'
+
+describe('CheckKishnamurthyNumber', () => {
+  it.each([1, 2, 145, 40585])('returns true for %i', (num) => {
+    expect(CheckKishnamurthyNumber(num)).toBe(true)
+  })
+
+  it.each([0, 3, 4, 5, 100, 146, 1019823, -1])(
+    'returns false for %i',
+    (num) => {
+      expect(CheckKishnamurthyNumber(num)).toBe(false)
+    }
+  )
+
+  it('should throw when input is not a number', () => {
+    expect(() => CheckKishnamurthyNumber('2')).toThrowError()
+  })
+})