LibJS: Don't create StringOrSymbol(String) if from_value() fails

If value.to_string() throws an exception and returns a null string we
must create an invalid StringOrSymbol, not one from the null string
(which ASSERT()s).

1 files changed, 6 insertions, 3 deletions

diff --git a/Libraries/LibJS/Runtime/StringOrSymbol.h b/Libraries/LibJS/Runtime/StringOrSymbol.h
index 3273e7f640..b21c1785c6 100644
--- a/Libraries/LibJS/Runtime/StringOrSymbol.h
+++ b/Libraries/LibJS/Runtime/StringOrSymbol.h
@@ -37,11 +37,14 @@ class StringOrSymbol {
 public:
     static StringOrSymbol from_value(GlobalObject& global_object, Value value)
     {
+        if (value.is_empty())
+            return {};
         if (value.is_symbol())
             return &value.as_symbol();
-        if (!value.is_empty())
-            return value.to_string(global_object);
-        return {};
+        auto string = value.to_string(global_object);
+        if (string.is_null())
+            return {};
+        return string;
     }
 
     StringOrSymbol() = default;