Add isISSN().

CHANGELOG.md

@@ -4,6 +4,8 @@
   ([#585](https://github.com/chriso/validator.js/pull/585))
 - Added support for greater or less than in `isFloat()`
   ([#544](https://github.com/chriso/validator.js/issues/544))
+- Added support for ISSN validation via `isISSN()`
+  ([#589](https://github.com/chriso/validator.js/pull/589))
 
 #### 6.0.0
 

README.md

@@ -78,6 +78,7 @@ Passing anything other than a string is an error.
 - **isHexadecimal(str)** - check if the string is a hexadecimal number.
 - **isIP(str [, version])** - check if the string is an IP (version 4 or 6).
 - **isISBN(str [, version])** - check if the string is an ISBN (version 10 or 13).
+- **isISSN(str [, options])** - check if the string is an [ISSN](https://en.wikipedia.org/wiki/International_Standard_Serial_Number). `options` is an object which defaults to `{ case_sensitive: false }`.
 - **isISIN(str)** - check if the string is an [ISIN][ISIN] (stock/security identifier).
 - **isISO8601(str)** - check if the string is a valid [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601) date.
 - **isIn(str, values)** - check if the string is in a array of allowed values.

index.js

@@ -180,6 +180,10 @@ var _isISBN = require('./lib/isISBN');
 
 var _isISBN2 = _interopRequireDefault(_isISBN);
 
+var _isISSN = require('./lib/isISSN');
+
+var _isISSN2 = _interopRequireDefault(_isISSN);
+
 var _isMobilePhone = require('./lib/isMobilePhone');
 
 var _isMobilePhone2 = _interopRequireDefault(_isMobilePhone);
@@ -269,7 +273,7 @@ var validator = {
   isDate: _isDate2.default, isAfter: _isAfter2.default, isBefore: _isBefore2.default,
   isIn: _isIn2.default,
   isCreditCard: _isCreditCard2.default,
-  isISIN: _isISIN2.default, isISBN: _isISBN2.default,
+  isISIN: _isISIN2.default, isISBN: _isISBN2.default, isISSN: _isISSN2.default,
   isMobilePhone: _isMobilePhone2.default,
   isCurrency: _isCurrency2.default,
   isISO8601: _isISO2.default,

src/index.js

@@ -58,6 +58,7 @@ import isCreditCard from './lib/isCreditCard';
 
 import isISIN from './lib/isISIN';
 import isISBN from './lib/isISBN';
+import isISSN from './lib/isISSN';
 
 import isMobilePhone from './lib/isMobilePhone';
 
@@ -103,7 +104,7 @@ const validator = {
   isDate, isAfter, isBefore,
   isIn,
   isCreditCard,
-  isISIN, isISBN,
+  isISIN, isISBN, isISSN,
   isMobilePhone,
   isCurrency,
   isISO8601,

src/lib/isISSN.js

@@ -0,0 +1,20 @@
+import assertString from './util/assertString';
+
+const issn = /^\d{4}-\d{3}[\dX]$/;
+
+export default function isISSN(str, options = {}) {
+  assertString(str);
+  const testIssn = options.case_sensitive ? issn : new RegExp(issn, 'i');
+  if (!testIssn.test(str)) {
+    return false;
+  }
+  const issnDigits = str.replace('-', '');
+  let position = 8;
+  let checksum = 0;
+  for (const digit of issnDigits) {
+    const digitValue = digit.toUpperCase() === 'X' ? 10 : +digit;
+    checksum += digitValue * position;
+    --position;
+  }
+  return checksum % 11 === 0;
+}

test/validators.js

@@ -1851,6 +1851,35 @@ describe('Validators', function () {
     });
   });
 
+  it('should validate ISSNs', function () {
+    test({
+      validator: 'isISSN',
+      valid: [
+        '0378-5955',
+        '0000-0000',
+        '2434-561X',
+        '2434-561x',
+      ],
+      invalid: [
+        '0378-5954',
+        '0000-0001',
+        '0378-123',
+        '037-1234',
+        '0',
+      ],
+    });
+    test({
+      validator: 'isISSN',
+      args: [{ case_sensitive: true }],
+      valid: [
+        '2434-561X',
+      ],
+      invalid: [
+        '2434-561x',
+      ],
+    });
+  });
+
   it('should validate JSON', function () {
     test({
       validator: 'isJSON',

validator.js

@@ -1027,6 +1027,49 @@
         return false;
       }
 
+      var issn = /^\d{4}-\d{3}[\dX]$/;
+
+      function isISSN(str) {
+        var options = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : {};
+
+        assertString(str);
+        var testIssn = options.case_sensitive ? issn : new RegExp(issn, 'i');
+        if (!testIssn.test(str)) {
+          return false;
+        }
+        var issnDigits = str.replace('-', '');
+        var position = 8;
+        var checksum = 0;
+        var _iteratorNormalCompletion = true;
+        var _didIteratorError = false;
+        var _iteratorError = undefined;
+
+        try {
+          for (var _iterator = issnDigits[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
+            var digit = _step.value;
+
+            var digitValue = digit.toUpperCase() === 'X' ? 10 : +digit;
+            checksum += digitValue * position;
+            --position;
+          }
+        } catch (err) {
+          _didIteratorError = true;
+          _iteratorError = err;
+        } finally {
+          try {
+            if (!_iteratorNormalCompletion && _iterator.return) {
+              _iterator.return();
+            }
+          } finally {
+            if (_didIteratorError) {
+              throw _iteratorError;
+            }
+          }
+        }
+
+        return checksum % 11 === 0;
+      }
+
       /* eslint-disable max-len */
       var phones = {
         'ar-DZ': /^(\+?213|0)(5|6|7)\d{8}$/,
@@ -1367,7 +1410,7 @@
         isDate: isDate, isAfter: isAfter, isBefore: isBefore,
         isIn: isIn,
         isCreditCard: isCreditCard,
-        isISIN: isISIN, isISBN: isISBN,
+        isISIN: isISIN, isISBN: isISBN, isISSN: isISSN,
         isMobilePhone: isMobilePhone,
         isCurrency: isCurrency,
         isISO8601: isISO8601,