callbacks should now be called correctly

lib/cart.js

@@ -30,21 +30,35 @@ function Cart(options) {
 sys.inherits(Cart, ConnectStore);
 
 Cart.prototype.get = function (hash, fn) {
-  this.db.get(hash, fn);
+    this.db.get(hash, function (err, val) {
+        if (err) throw err;
+        if (val) {
+            fn(null, val);
+        }
+        else {
+            fn();
+        }
+    })
 };
 
 Cart.prototype.set = function (hash, sess, fn) {
-    this.db.set(hash, JSON.stringify(sess), fn);
+    this.db.set(hash, JSON.stringify(sess), function (err) {
+        if (err) throw err;
+        if (fn) fn();
+    });
 };
 
 Cart.prototype.destroy = function (hash, fn) {
-    this.db.remove(hash, fn);
+    this.db.remove(hash, function (err) {
+        if (err) throw err;
+        if (fn) fn();
+    });
 };
 
 Cart.prototype.length = function (fn) {
     process.nextTick(function () {
         this.db.length(function (err, len) {
-            fn(len);
+            fn(null, len);
         });
     });
 };
@@ -54,7 +68,9 @@ Cart.prototype.clear = function (fn) {
         function (err, key, value) {
             this.db.remove(key);
         },
-        function () { fn() }
+        function () {
+            if (fn) fn()
+        }
     );
 };