It was very intentional. The original developer wanted to create an event loop based system because at the time the C hackers had begun to learn how fast those

It was very intentional. The original developer wanted to create an event loop based system because at the time the C hackers had begun to learn how fast those systems could be for the purpose the parent comment mentioned (io bound, network servers, etc.) and instead of using something like lua he chose javascript to give it wider appeal.