fixed constructor default options bug!

.gitignore

@@ -1 +1,2 @@
 node_modules
+*.log

package.json

@@ -20,7 +20,8 @@
         "url": "https://github.com/WQTeam/web-storage-cache/issues"
     },
     "scripts": {
-        "test": "grunt test"
+        "test": "grunt test",
+        "build": "grunt build"
     },
     "devDependencies": {
         "chai": "~2.1.0",

src/web-storage-cache.js

@@ -16,6 +16,7 @@
     "use strict";
 
     var _maxExpireDate = new Date('Fri, 31 Dec 9999 23:59:59 UTC');
+    var _defaultExpire = _maxExpireDate;
 
     // https://github.com/jeromegn/Backbone.localStorage/blob/master/backbone.localStorage.js#L63
     var defaultSerializer = {
@@ -115,7 +116,7 @@
     function CacheItemConstructor (value, exp) {
         // createTime
         this.c = (new Date()).getTime();
-        exp = exp || _maxExpireDate;
+        exp = exp || _defaultExpire;
         var expires = _getExpiresDate(exp);
         // expiresTime
         this.e = expires.getTime();
@@ -317,6 +318,14 @@ function CacheConstructor (options) {
 
     var opt = _extend(defaults, options);
 
+    var expires = opt.exp;
+
+    if (expires && typeof expires !== 'number' && !_isValidDate(expires)) {
+        throw new Error('Constructor `exp` parameter cannot be converted to a valid Date instance');
+    } else {
+        _defaultExpire = expires;
+    }
+
     var storage = _getStorageInstance(opt.storage);
 
     var isSupported = _isStorageSupported(storage);

test/unit/test.api.js

@@ -7,7 +7,9 @@ describe('WebStorageCache', function() {
     'use strict';
     before(function() {
         clearStorage();
-        this.wsCache = new WebStorageCache(storage);
+        this.wsCache = new WebStorageCache({
+            storage: storage
+        });
     });
     after(function() {
         clearStorage();
@@ -28,6 +30,32 @@ describe('WebStorageCache', function() {
             expect(wsCache.add).to.be.a('function');
             expect(wsCache.replace).to.be.a('function');
         });
+        it('should set default expires success with number', function(done){
+            this.timeout(5000);
+            var cache = new WebStorageCache({
+                exp: 3
+            });
+            cache.set('testDefaultExpires', '1');
+            expect(cache.get('testDefaultExpires')).to.equal('1');
+            setTimeout(function() {
+                expect(cache.get('testDefaultExpires')).to.be.a('null');
+                done();
+            }, 3000);
+        });
+        it('should set default expires success with an outdate date', function(){
+            var cache = new WebStorageCache({
+                exp: new Date('1990 1 12')
+            });
+            cache.set('testDefaultExpires', '3');
+            expect(cache.get('testDefaultExpires')).to.be.a('null');
+        });
+        it('should set default expires success with an future date', function(){
+            var cache = new WebStorageCache({
+                exp: new Date('9999 1 12')
+            });
+            cache.set('testDefaultExpires', 1111);
+            expect(cache.get('testDefaultExpires')).to.equal(1111);
+        });
     });
     describe('#isSupported', function() {
         it('should be true', function() {