diff --git a/lib/once.js b/lib/once.js
new file mode 100644
index 000000000..369ee162e
--- /dev/null
+++ b/lib/once.js
@@ -0,0 +1,8 @@
+module.exports = function (f) {
+    var called;
+    return function () {
+        if (called) { return; }
+        called = true;
+        f.apply(this, Array.prototype.slice.call(arguments));
+    };
+};