... IIRC , there is a node-spidermonkey version,but Mozilla doesn't seem to be interested in working seriously on that project. Which is crazy because one would expect Mozilla to do exactly that.
Last I heard, the node guys were quite adverse at maintaining both node-v8 and node-spidermonkey. I don't blame them ;)
And that doesn't help that the people who started node-spidermonkey left Mozilla and afaik can't contribute to open source projects that are not explicitly vetted by their current employer.