From 65a55b6d29c639dc11b67ec9a8c0122cf07b3051 Mon Sep 17 00:00:00 2001
From: Joshua Peek <josh@joshpeek.com>
Date: Thu, 5 Mar 2015 11:07:33 -0800
Subject: [PATCH] Fix when no output

---
 lib/execjs/external_runtime.rb | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/execjs/external_runtime.rb b/lib/execjs/external_runtime.rb
index 7cb0a9d..811dd69 100644
--- a/lib/execjs/external_runtime.rb
+++ b/lib/execjs/external_runtime.rb
@@ -213,7 +213,9 @@ module ExecJS
 
       def exec_runtime_error(output)
         error = RuntimeError.new(output)
-        lineno = output.split("\n")[0][/:(\d+)$/, 1] || 1
+        lines = output.split("\n")
+        lineno = lines[0][/:(\d+)$/, 1] if lines[0]
+        lineno ||= 1
         error.set_backtrace(["(execjs):#{lineno}"] + caller)
         error
       end