Q:

Node.js or Express.js REST API document generator

I'm working on a restAPI using Express.js and I'm wondering if there is a way for me to generate API documents that allow a user to view API definitions or possibly even try out the API call? 

A:

What you are looking for is a good JavaScript documentation generator.   I found a decent one here http://apidocjs.com/example/.
This will allow you to use just Express as OP asked.   
Swagger isn't for generating docs, it's for making APIs.   So you are going to need to learn a full system to get that feature. 
I found a couple more here that I haven't fully looked into yet which seem promising:
Docco here JSDoc here and an  article on Documentor for Node

A:

Swagger is an amazing project for auto generating API documentation.  It includes an Express module.  
http://swagger.io/
https://github.com/wordnik/swagger-node-express

