From c8d109ee3634ec8973338bdbf73dbaf3bd20afe5 Mon Sep 17 00:00:00 2001
From: daurnimator <quae@daurnimator.com>
Date: Wed, 27 Sep 2017 23:20:21 +1000
Subject: src/loadlib.js: Check that JS library returns expected type(s)

---
 src/loadlib.js | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/loadlib.js b/src/loadlib.js
index e7626ab..7a50556 100644
--- a/src/loadlib.js
+++ b/src/loadlib.js
@@ -56,7 +56,12 @@ if (WEB) {
                 return null;
             }
             let res = func(fengari);
-            return res;
+            if (typeof res === "function" || (typeof res === "object" && res !== null)) {
+                return res;
+            } else {
+                lua.lua_pushstring(L, lua.to_luastring(`library returned unexpected type (${typeof res})`));
+                return null;
+            }
         } else {
             lua.lua_pushstring(L, lua.to_luastring(`${xhr.status}: ${xhr.statusText}`));
             return null;
-- 
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