So siehts ganz gut aus !

node_modules/es5-ext/array/#/diff.js

@@ -0,0 +1,13 @@
+"use strict";
+
+var value    = require("../../object/valid-value")
+  , contains = require("./contains")
+  , filter   = Array.prototype.filter;
+
+module.exports = function (other) {
+	value(this);
+	value(other);
+	return filter.call(this, function (item) {
+		return !contains.call(other, item);
+	});
+};