Update function to check for decimal digits.

Author: russom-g

sprint-3-stretch-exercises/credit-card-validator.js

@@ -1,9 +1,9 @@
 export function creditCardValidator(cardNumber) {
-  // rejects the number if itn's exactly 16 characters or contain non-digits
-  if (cardNumber.length !== 16 || !Number.isInteger(Number(cardNumber))) {
+  // rejects the number if itn's exactly 16 characters
+  if (cardNumber.length !== 16) {
     return false;
   }
-
+  // the last digit must be even, so reject it if dividing by 2 leaves a reminder
   if (cardNumber.slice(-1) % 2 !== 0) {
     return false;
   }
@@ -12,7 +12,10 @@ export function creditCardValidator(cardNumber) {
   let digitSum = 0;
 
   for (const digit of cardNumber) {
-    // the last digit must be even, so reject it if dividing by 2 leaves a reminder
+    // every character must be a digit from 0 to 9
+    if (digit < "0" || digit > "9") {
+      return false;
+    }
     digitSum += Number(digit);
 
     // if any digit differs from the first one, at least two different digits are used
@@ -21,7 +24,7 @@ export function creditCardValidator(cardNumber) {
     }
   }
 
-  // the number needs two different digits and a digit sum greater than 16
+  // needs two different digits and a digit sum greater than 16
   if (!hasDifferentDigit || digitSum <= 16) {
     return false;
   }