Unlike e.g. in Python, in Node people aren't so eager to use (partially) autogenerated docs that document functions and classes. Sometimes this is an advantage (because handwritten docs are usually better), sometimes not (when the docs no longer match the actual API).

As to whether Node.js projects in general are better documented or worse than the average project in other languages... I dunno, that seems kind of anecdotal. Basic building blocks like `async`, `underscore`, `commander` etc. all have great documentation.