diff --git a/modules/juce_core/javascript/juce_Javascript.cpp b/modules/juce_core/javascript/juce_Javascript.cpp
index ec78482cce..3ffedae69f 100644
--- a/modules/juce_core/javascript/juce_Javascript.cpp
+++ b/modules/juce_core/javascript/juce_Javascript.cpp
@@ -83,6 +83,12 @@ static qjs::JSValue juceToQuickJs (const var& v, qjs::JSContext* ctx)
 {
     using namespace qjs;
 
+    if (v.isVoid())
+        return JS_NULL;
+
+    if (v.isUndefined())
+        return JS_UNDEFINED;
+
     if (v.isInt())
         return JS_NewInt32   (ctx, static_cast<int> (v));
 
@@ -180,7 +186,7 @@ static qjs::JSValue juceToQuickJs (const var& v, qjs::JSContext* ctx)
         return result;
     }
 
-    jassert (v.isVoid());
+    jassertfalse;
     return JS_UNDEFINED;
 }