The ESP8266 may be a good candidate. tmrmr already said in these comments that some other company had ported another JS engine to the thing. And the world isn't

The ESP8266 may be a good candidate. tmrmr already said in these comments that some other company had ported another JS engine to the thing. And the world isn't just Arduinos, Raspberry Pis and other nicely-packaged "hacking" solutions.