acces collections from a database MongoDb in Derby.js (node.js)

I have a collection called "textDocuments" and I want to get the value of "content" from that collection (wich must be a string) and create a file (wich contain that string) and upload it on a Dropbox account. I dont know how to acces that string in my collection and create that file in my Derby.js project. Can someone help me ?

with "mongo" command in terminal I connect to my database. I type "use project" ("project" is my database name) and when I type "db.textDocuments.find()" a row that appear is like this:

{ "content" : "sssss ffffdddfd dddd fffffddfdsssdddfff fffdd fddffd  fddfffddf fdfdfdfddfd dfddf dfdffd dff dffdf fdfd fffff ffdfdfdfd fffffddffd fdfdfdfdfsdf sdfsdfs", "_type" : "http://sharejs.org/types/JSONv0", "_v" : 151, "_id" : "bbe876e4-8483-4f87-9b29-1b31691e506a" }