MongoJS Node.js modules:“db is not undefined”

Question

I'm new to Node.js, MongoDB and MongoJS.

I have app.js which is the server I run from my command line with node app.js . On a local machine with OS X 10.9.1 with Node.js v0.10.28.

In app.js I have (as snippets)

var db = require('./database');

var blog = require('./classes/blog');

and database.js has

var db = require("mongojs");

db.connect('mydb',  ["Users", "Posts"]);

and /classes/blog.js has

function load(OnDone) {
    if (db.connected) {
        OnDone();
    }
}

When I call blog.load() I get

ReferenceError: db is not defined
    at Object.load (node/classes/blog.js:13:6)
    at node/app.js:36:7
    at Server.onRequest (node/server.js:35:12)
    at Server.EventEmitter.emit (events.js:98:17)
    at HTTPParser.parser.onIncoming (http.js:2108:12)
    at HTTPParser.parserOnHeadersComplete [as onHeadersComplete] (http.js:121:23)
    at Socket.socket.ondata (http.js:1966:22)
    at TCP.onread (net.js:527:27)

Everything in my app works as expected except when I try to call my load() function which uses the db var that I thought I declared in app.js .

Why would db be undefined? Am I using modules wrong?

Note: if you can't tell, I extracted these lines of codes from my scripts since my app so far is relatively long for a SO question and I don't want to show it all unless I need to.

Answer 1

I believe Node.js modules are contained so do not have access to variables defined in their parents (as I assumed).

I moved db to the global namespace (I removed var ) and it's working now.