From 6139e8893a281f45554337a8a8f059c98b7d58f0 Mon Sep 17 00:00:00 2001
From: Kevin Schaaf <kschaaf@google.com>
Date: Wed, 13 Feb 2019 18:16:52 -0800
Subject: [PATCH] Add arg length check

---
 lib/mixins/property-effects.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/mixins/property-effects.js b/lib/mixins/property-effects.js
index dccf2a0051..5e0e2b753d 100644
--- a/lib/mixins/property-effects.js
+++ b/lib/mixins/property-effects.js
@@ -2226,7 +2226,7 @@ export const PropertyEffects = dedupingMixin(superClass => {
         }
         // When the `legacyUndefined` flag is enabled, pass a no-op value
         // so that the observer, computed property, or compound binding is aborted.
-        if (legacyUndefined && value === undefined) {
+        if (legacyUndefined && value === undefined && args.length > 1) {
           return NOOP;
         }
         values[i] = value;