fix: factorial function (TheAlgorithms#1093)

itsAkshayDubey · web-flow · commit 61c9e8b372e6 · 2022-09-07T15:00:35.000+05:30
diff --git a/Maths/Factorial.js b/Maths/Factorial.js
@@ -19,18 +19,18 @@ const calcRange = (num) => {
 
 const calcFactorial = (num) => {
   if (num === 0) {
-    return 'The factorial of 0 is 1.'
+    return 1
   }
   if (num < 0) {
-    return 'Sorry, factorial does not exist for negative numbers.'
+    throw Error('Sorry, factorial does not exist for negative numbers.')
   }
   if (!num) {
-    return 'Sorry, factorial does not exist for null or undefined numbers.'
+    throw Error('Sorry, factorial does not exist for null or undefined numbers.')
   }
   if (num > 0) {
     const range = calcRange(num)
     const factorial = range.reduce((a, c) => a * c, 1)
-    return `The factorial of ${num} is ${factorial}`
+    return factorial
   }
 }
 
diff --git a/Maths/test/Factorial.test.js b/Maths/test/Factorial.test.js
@@ -2,30 +2,20 @@ import { calcFactorial } from '../Factorial'
 
 describe('calcFactorial', () => {
   it('should return a statement for value "0"', () => {
-    expect(calcFactorial(0)).toBe('The factorial of 0 is 1.')
+    expect(calcFactorial(0)).toBe(1)
   })
 
-  it('should return a statement for "null" and "undefined"', () => {
-    const nullFactorial = calcFactorial(null)
-    const undefinedFactorial = calcFactorial(undefined)
-
-    expect(nullFactorial).toBe(
-      'Sorry, factorial does not exist for null or undefined numbers.'
-    )
-    expect(undefinedFactorial).toBe(
-      'Sorry, factorial does not exist for null or undefined numbers.'
-    )
+  it('should throw error for "null" and "undefined"', () => {
+    expect(() => { calcFactorial(null) }).toThrow(Error)
+    expect(() => { calcFactorial(undefined) }).toThrow(Error)
   })
 
-  it('should not support negative numbers', () => {
-    const negativeFactorial = calcFactorial(-5)
-    expect(negativeFactorial).toBe(
-      'Sorry, factorial does not exist for negative numbers.'
-    )
+  it('should throw error for negative numbers', () => {
+    expect(() => { calcFactorial(-1) }).toThrow(Error)
   })
 
   it('should return the factorial of a positive number', () => {
     const positiveFactorial = calcFactorial(3)
-    expect(positiveFactorial).toBe('The factorial of 3 is 6')
+    expect(positiveFactorial).toBe(6)
   })
 })

Original file line number	Diff line number	Diff line change
`@@ -19,18 +19,18 @@ const calcRange = (num) => {`
`19`	`19`
`20`	`20`	`const calcFactorial = (num) => {`
`21`	`21`	`if (num === 0) {`
`22`		`- return 'The factorial of 0 is 1.'`
	`22`	`+ return 1`
`23`	`23`	`}`
`24`	`24`	`if (num < 0) {`
`25`		`- return 'Sorry, factorial does not exist for negative numbers.'`
	`25`	`+ throw Error('Sorry, factorial does not exist for negative numbers.')`
`26`	`26`	`}`
`27`	`27`	`if (!num) {`
`28`		`- return 'Sorry, factorial does not exist for null or undefined numbers.'`
	`28`	`+ throw Error('Sorry, factorial does not exist for null or undefined numbers.')`
`29`	`29`	`}`
`30`	`30`	`if (num > 0) {`
`31`	`31`	`const range = calcRange(num)`
`32`	`32`	`const factorial = range.reduce((a, c) => a * c, 1)`
`33`		- return `The factorial of ${num} is ${factorial}`
	`33`	`+ return factorial`
`34`	`34`	`}`
`35`	`35`	`}`
`36`	`36`