Why ScriptResult.value is undefined even though the script exported something, or null when there is nothing to explain — including when it exported nothing at all.

Reads like 'index is a Map' or 'the value is a function' — the field named, rather than silently handed back as {}. Reading it is optional and ignoring it is fine: a script whose default export is a main() function is an ordinary script, not a broken one, so this never affects ScriptResult.ok.