From 586721462c0a90198b2b0119f52812857d1a2852 Mon Sep 17 00:00:00 2001
From: Eric Vergnaud <eric.vergnaud@wanadoo.fr>
Date: Sat, 13 Feb 2021 15:09:34 +0800
Subject: [PATCH] Fix #3078

---
 runtime/JavaScript/src/antlr4/Utils.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/runtime/JavaScript/src/antlr4/Utils.js b/runtime/JavaScript/src/antlr4/Utils.js
index 8eed91a2c..66cf13152 100644
--- a/runtime/JavaScript/src/antlr4/Utils.js
+++ b/runtime/JavaScript/src/antlr4/Utils.js
@@ -4,7 +4,7 @@
  */
 
 function arrayToString(a) {
-    return "[" + a.join(", ") + "]";
+    return Array.isArray(a) ? ("[" + a.join(", ") + "]") : "null";
 }
 
 String.prototype.seed = String.prototype.seed || Math.round(Math.random() * Math.pow(2, 32));