[test][api] Added expiry validation and tests, also introduced brower…

… support

lib/creditcard.js

@@ -1,3 +1,4 @@
+(function (exports) {
 'use strict';
 
 /**
@@ -135,6 +136,30 @@ exports.validate = function validate(number) {
   return (sum % 10 === 0) && (sum > 0);
 };
 
+/**
+ * Validates the expiry number.
+ *
+ * @param {String|Number} month
+ * @param {String|Number} year
+ * @return {Boolean}
+ */
+exports.expiry = function expiry(month, year) {
+  // number conversion
+  month = +month;
+  year = +year;
+
+  // incorrect numbers should fail fast
+  if (!month || year) return false;
+
+  var date = new Date()
+    , now = +date;
+
+  date.setFullYear(year);
+  date.setMonth(--month);
+
+  return +date >= now;
+};
+
 /**
  * Applies PAN truncation to the given creditcard. PAN (primary account number)
  * trunction is a "technology" that prevents most of the digits of a creditcard
@@ -179,3 +204,4 @@ exports.parse = function parse(number) {
     , validates: exports.validate(number)   // Does the creditcard validate
   };
 };
+}(typeof exports !== 'undefined' ? exports : (creditcard = {})));

test/creditcard.test.js

@@ -93,3 +93,17 @@ describe('creditcard#parse', function () {
     expect(data.validates).to.equal(true);
   });
 });
+
+describe('creditcard#expiry', function () {
+  it('should validate the expiry', function () {
+    var today = new Date();
+
+    expect(creditcard.expiry((today.getMonth() + 1), today.getFullYear()));
+  });
+
+  it('should not validate the expiry', function () {
+    expect(creditcard.expiry('06', '1990')).to.equal(false);
+    expect(creditcard.expiry('06', '12')).to.equal(false);
+    expect(creditcard.expiry(6, 12)).to.equal(false);
+  });
+});