You can check this code <a href="https:&#x2F;&#x2F;github.com&#x2F;espruino&#x2F;Espruino&#x2F;blob&#x2F;master&#x2F;README.md" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;espruino&#x2F;Espruino&#x2F;blob&#x2F;master&#x2F;README.md</a><p>I quote<p>&quot;Espruino is a JavaScript interpreter for microcontrollers. It is designed to fit into devices with as little as 128kB Flash and 8kB RAM.&quot;<p>It could be a good example of a small js interpreter. I remember the author said to be 95% compatible with real js. That was a couple of years ago.