I just release an npm package called rundown. It is an RDoc document
parser for Javascript/Node.js.

The project is in it’s infancy and being built piecemeal by converting
the showdown.js Markdown library to handle RDoc format. So far I have
implemented support for headers and links. If you find this project
useful and have the skills, please help implement missing features.

Read more at GitHub - rubyworks/rundown: Javascript RDoc Parser.