fix: Enhance error handling in factorial function (TheAlgorithms#1430)

Author: yongeazi143

Recursive/Factorial.js

@@ -9,17 +9,14 @@
  */
 
 const factorial = (n) => {
- if (!Number.isInteger(n)) {
- throw new RangeError('Not a Whole Number')
- }
-
- if (n < 0) {
- throw new RangeError('Not a Positive Number')
+ if (!Number.isInteger(n) || n < 0) {
+ throw new RangeError('Input should be a non-negative whole number')
  }
 
  if (n === 0) {
  return 1
  }
+
  return n * factorial(n - 1)
 }
 

Recursive/test/Factorial.test.js

@@ -10,10 +10,20 @@ describe('Factorial', () => {
  })
 
  it('Throw Error for Invalid Input', () => {
- expect(() => factorial('-')).toThrow('Not a Whole Number')
- expect(() => factorial(null)).toThrow('Not a Whole Number')
- expect(() => factorial(undefined)).toThrow('Not a Whole Number')
- expect(() => factorial(3.142)).toThrow('Not a Whole Number')
- expect(() => factorial(-1)).toThrow('Not a Positive Number')
+ expect(() => factorial('-')).toThrow(
+ 'Input should be a non-negative whole number'
+ )
+ expect(() => factorial(null)).toThrow(
+ 'Input should be a non-negative whole number'
+ )
+ expect(() => factorial(undefined)).toThrow(
+ 'Input should be a non-negative whole number'
+ )
+ expect(() => factorial(3.142)).toThrow(
+ 'Input should be a non-negative whole number'
+ )
+ expect(() => factorial(-1)).toThrow(
+ 'Input should be a non-negative whole number'
+ )
  })
 })