(fix): validator method

JuanMaRuiz · Sep 28, 2021 · 121f2be · 121f2be
1 parent 99d8d4a
commit 121f2be
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Showing 2 changed files with 9 additions and 4 deletions.
diff --git a/__test__/validator.test.js b/__test__/validator.test.js
@@ -1,7 +1,5 @@
 import validate from './../src/validator.js';
 
-// Valid ISBN 8497364678, 84-481-2231-3, 978-84-415-2682-2
-
 test('validate method should return TRUE if passed value is a valid 10 numbers ISBN ', () => {
   expect(validate('84 - 481 - 2231 - 3')).toBe(true);
   expect(validate('84 - 481 2231- 3')).toBe(true);
@@ -20,6 +18,7 @@ test('validate method should return FALSE if passed string does not have the cor
 test('validate method should return TRUE if passed value is a valid 13 numbers ISBN ', () => {
   expect(validate('978-84-415-2682-2')).toBe(true);
   expect(validate('978-34-2628-155-0')).toBe(true);
+  expect(validate('978-2-27-509083-2')).toBe(true);
 });
 
 test('validate method should return FALSE if passed value is NOT a valid 13 numbers ISBN ', () => {

diff --git a/src/validator.js b/src/validator.js
@@ -21,7 +21,7 @@ const IsValidIsbn = isbn => {
     result = controlDigit.toUpperCase() === 'X' ? modulus === 10 : modulus === parseInt(controlDigit);
 
   } else {
-    const elementsSum = isbnAsArray.map((el, index) => (index + 1) % 2 === 0 ? el * 1 : el * 3).reduce((acc, curr) => acc + curr);
+    const elementsSum = isbnAsArray.map((el, index) => index % 2 === 0 ? el * 1 : el * 3).reduce((acc, curr) => acc + curr);
 
     result = getControlDigit(elementsSum) === parseInt(controlDigit);
   }
@@ -30,7 +30,13 @@ const IsValidIsbn = isbn => {
 };
 
 const getControlDigit = (sum, acc = 0) => {
-  return sum % 10 !== 0 ? getControlDigit(sum + 1, acc + 1) : acc;
+  if (sum % 10 !== 0) {
+    return getControlDigit(sum + 1, acc + 1);
+  } else if (sum % 10 === 0 && acc === 0) {
+    return 0;
+  } else {
+    return acc;
+  }
 };
 
 const validate = (isbn) => {