From d44969a2119975ed66fc9e534c1bfa93a77faaf9 Mon Sep 17 00:00:00 2001
From: Kevin Schaaf <kschaaf@google.com>
Date: Mon, 23 Jul 2018 10:41:33 -0700
Subject: [PATCH] Ensure instanceof works after babel ES5 compilation

---
 lib/legacy/legacy-data-mixin.html | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/lib/legacy/legacy-data-mixin.html b/lib/legacy/legacy-data-mixin.html
index 21124629ca..eef8802a57 100644
--- a/lib/legacy/legacy-data-mixin.html
+++ b/lib/legacy/legacy-data-mixin.html
@@ -19,6 +19,9 @@
     constructor(message) {
       super(message);
       this.name = this.constructor.name;
+      // Affordances for ensuring instanceof works after babel ES5 compilation
+      this.constructor = UndefinedArgumentError;
+      this.__proto__ = UndefinedArgumentError.prototype;
     }
   };