diff --git a/mithril.js b/mithril.js
index b5d5203c..9677ba16 100644
--- a/mithril.js
+++ b/mithril.js
@@ -695,15 +695,6 @@ var coreRenderer = function($window) {
 			}
 		}
 	}
-	function once(f) {
-		var called = false
-		return function() {
-			if (!called) {
-				called = true
-				f()
-			}
-		}
-	}
 	function removeNode(vnode, context) {
 		var expected = 1, called = 0
 		if (vnode.attrs && vnode.attrs.onbeforeremove) {