MarquisF · November 6, 2015 11:52 · Jul 1, 2011
diff --git a/gistfile1.txt b/gistfile1.txt
@@ -0,0 +1,39 @@
+/**
+    Code copyright Dustin Diaz and Ross Harmes, Pro JavaScript Design Patterns.
+**/
+
+// Constructor.
+var Interface = function (name, methods) {
+        if (arguments.length != 2) {
+            throw new Error("Interface constructor called with " + arguments.length + "arguments, but expected exactly 2.");
+        }
+        this.name = name;
+        this.methods = [];
+        for (var i = 0, len = methods.length; i < len; i++) {
+            if (typeof methods[i] !== 'string') {
+                throw new Error("Interface constructor expects method names to be " + "passed in as a string.");
+            }
+            this.methods.push(methods[i]);
+        }
+    };
+
+
+// Static class method.
+Interface.ensureImplements = function (object) {
+    if (arguments.length < 2) {
+        throw new Error("Function Interface.ensureImplements called with " + arguments.length + "arguments, but expected at least 2.");
+    }
+    for (var i = 1, len = arguments.length; i < len; i++) {
+        var interface = arguments[i];
+        if (interface.constructor !== Interface) {
+            throw new Error("Function Interface.ensureImplements expects arguments" + "two and above to be instances of Interface.");
+        }
+        for (var j = 0, methodsLen = interface.methods.length; j < methodsLen; j++) {
+            var method = interface.methods[j];
+            if (!object[method] || typeof object[method] !== 'function') {
+                throw new Error("Function Interface.ensureImplements: object " + "does not implement the " + interface.name + " interface. Method " + method + " was not found.");
+            }
+        }
+    }
+};
+