Improve input validation of isDivisible

Masa-Shin · Masa-Shin · commit 469a0e06c831 · 2021-05-05T14:22:10.000+09:00
- Use Number.isFinite() for validation
- Throw an error instead of returning a string
- Instead of returning a string, return false when divisor === 0 since no numbers are in fact divisible by 0.
diff --git a/Maths/IsDivisible.js b/Maths/IsDivisible.js
@@ -1,15 +1,15 @@
 // Checks if a number is divisible by another number.
 
-const isDivisible = (num1, num2) => {
-  if (isNaN(num1) || isNaN(num2) || num1 == null || num2 == null) {
-    return 'All parameters have to be numbers'
+export const isDivisible = (num1, num2) => {
+  if (!Number.isFinite(num1) || !Number.isFinite(num2)) {
+    throw new Error('All parameters have to be numbers')
   }
   if (num2 === 0) {
-    return 'Not possible to divide by zero'
+    return false
   }
   return num1 % num2 === 0
 }
 
 console.log(isDivisible(10, 5)) // returns true
 console.log(isDivisible(123498175, 5)) // returns true
-console.log(isDivisible(99, 5)) // returns false
+console.log(isDivisible(99, 5)) // returns false

Original file line number	Diff line number	Diff line change
`@@ -1,15 +1,15 @@`
`1`	`1`	`// Checks if a number is divisible by another number.`
`2`	`2`
`3`		`-const isDivisible = (num1, num2) => {`
`4`		`- if (isNaN(num1) \|\| isNaN(num2) \|\| num1 == null \|\| num2 == null) {`
`5`		`- return 'All parameters have to be numbers'`
	`3`	`+export const isDivisible = (num1, num2) => {`
	`4`	`+ if (!Number.isFinite(num1) \|\| !Number.isFinite(num2)) {`
	`5`	`+ throw new Error('All parameters have to be numbers')`
`6`	`6`	`}`
`7`	`7`	`if (num2 === 0) {`
`8`		`- return 'Not possible to divide by zero'`
	`8`	`+ return false`
`9`	`9`	`}`
`10`	`10`	`return num1 % num2 === 0`
`11`	`11`	`}`
`12`	`12`
`13`	`13`	`console.log(isDivisible(10, 5)) // returns true`
`14`	`14`	`console.log(isDivisible(123498175, 5)) // returns true`
`15`		`-console.log(isDivisible(99, 5)) // returns false`
	`15`	`+console.log(isDivisible(99, 5)) // returns false`