documentation on what javascript features are supported in design document view scripts?

[fangq]

I am trying to write a few map functions to create views in a CouchDB database. Futon kept telling me that the script I wrote is not a valid function - despise that I used mostly standard JS features. After some debugging, I found that if I use standard string.match(//), string.replace(//,''), array.filter(), array.map() calls, or lambda functions ((x) => x * 2), it failed to save the document and threw an error.

This gives me the feeling that couchdb only supports a subset of JS, but could not find a document on what JS features are not supported.

Can someone let me know if such document exist? why couchjs does not support standard JS functions? from #1875 and #2345, it seems newer spidermonkey versions have been supported, but feel a bit surprised that it does not support these basic JS features.

my server has couchdb v3.3.2.

[rnewson]

This is determined by which version of spidermonkey your couchdb is built with.

[big-r81]

And you can show the used Spidermonkey engine with this endpoint.

[fangq]

thank you both for your prompt replies! the output of _node/_local/_versions shows that my OS (Ubuntu 18.04) has an old version of spidermonkey

"javascript_engine":{"version":"1.8.5","name":"spidermonkey"}

I will try couchdb on a newer server.