checking for existence of del() method before binding to it

lib/caching.js

@@ -1,4 +1,4 @@
-/*jshint maxcomplexity:10*/
+/*jshint maxcomplexity:15*/
 var caching = function (args) {
     args = args || {};
     var self = {};
@@ -78,7 +78,9 @@ var caching = function (args) {
 
     self.set = self.store.set.bind(self.store);
 
+    if (typeof self.store.del === 'function') {
         self.del = self.store.del.bind(self.store);
+    }
 
     if (typeof self.store.setex === 'function') {
         self.setex = self.store.setex.bind(self.store);

test/caching.unit.js

@@ -145,6 +145,23 @@ describe("caching", function () {
                 });
             }, 10);
         });
+
+        context("when store has no del() method", function () {
+            var fake_store;
+
+            beforeEach(function () {
+                fake_store = {
+                    get: function () {},
+                    set: function () {},
+                };
+            });
+
+            it("it doesn't throw an error", function () {
+                assert.doesNotThrow(function () {
+                    caching({store: fake_store});
+                });
+            });
+        });
     });
 
     describe("setex()", function () {