Merge pull request #1085 from tomtargosz/luhnCheck-bug

[FIX] Correctly implement luhnCheck

dist/_30s.es5.js

@@ -1486,7 +1486,7 @@
     });
     var lastDigit = arr.splice(0, 1)[0];
     var sum = arr.reduce(function (acc, val, i) {
-      return i % 2 !== 0 ? acc + val : acc + val * 2 % 9 || 9;
+      return i % 2 !== 0 ? acc + val : acc + (val * 2 > 9 ? val * 2 - 9 : val * 2);
     }, 0);
     sum += lastDigit;
     return sum % 10 === 0;

dist/_30s.esm.js

@@ -706,7 +706,7 @@ const luhnCheck = num => {
     .reverse()
     .map(x => parseInt(x));
   let lastDigit = arr.splice(0, 1)[0];
-  let sum = arr.reduce((acc, val, i) => (i % 2 !== 0 ? acc + val : acc + ((val * 2) % 9) || 9), 0);
+  let sum = arr.reduce((acc, val, i) => (i % 2 !== 0 ? acc + val : acc + (val * 2 > 9 ? val * 2 - 9 : val * 2)), 0);
   sum += lastDigit;
   return sum % 10 === 0;
 };

dist/_30s.js

@@ -712,7 +712,7 @@
       .reverse()
       .map(x => parseInt(x));
     let lastDigit = arr.splice(0, 1)[0];
-    let sum = arr.reduce((acc, val, i) => (i % 2 !== 0 ? acc + val : acc + ((val * 2) % 9) || 9), 0);
+    let sum = arr.reduce((acc, val, i) => (i % 2 !== 0 ? acc + val : acc + (val * 2 > 9 ? val * 2 - 9 : val * 2)), 0);
     sum += lastDigit;
     return sum % 10 === 0;
   };

test/_30s.js

@@ -709,7 +709,7 @@ const luhnCheck = num => {
     .reverse()
     .map(x => parseInt(x));
   let lastDigit = arr.splice(0, 1)[0];
-  let sum = arr.reduce((acc, val, i) => (i % 2 !== 0 ? acc + val : acc + ((val * 2) % 9) || 9), 0);
+  let sum = arr.reduce((acc, val, i) => (i % 2 !== 0 ? acc + val : acc + (val * 2 > 9 ? val * 2 - 9 : val * 2)), 0);
   sum += lastDigit;
   return sum % 10 === 0;
 };

test/luhnCheck.test.js

@@ -3,10 +3,16 @@ const {luhnCheck} = require('./_30s.js');
 test('luhnCheck is a Function', () => {
   expect(luhnCheck).toBeInstanceOf(Function);
 });
-test('validates identification number', () => {
-  expect(luhnCheck(6011329933655299)).toBeFalsy();
+test('invalidates an incorrect identification number', () => {
+  expect(luhnCheck(6011329933655298)).toBeFalsy();
 });
-test('validates identification number', () => {
+test('validates a correct identification number', () => {
+  expect(luhnCheck(6011329933655299)).toBeTruthy();
+});
+test('validates a correct identification number', () => {
+  expect(luhnCheck(5105105105105100)).toBeTruthy();
+});
+test('validates a correct identification number', () => {
   expect(luhnCheck('4485275742308327')).toBeTruthy();
 });
 test('validates identification number', () => {