Global variable express node.js

Question

I am trying to get variables that I can get everywhere in my code I found a solution but that's not very clean

//environment.js    
module.exports.appName = "appName";

and my app.js

var express = require('express')
, routes = require('./routes/main')
, user = require('./routes/user')
, http = require('http')
, path = require('path');

var app = express();

environment = require('./environment');

app.configure(function(){
app.set('port', process.env.PORT || 3000);
app.set('views', __dirname + '/views');
app.set('view engine', 'jade');
app.use(express.favicon());
app.use(express.logger('dev'));
app.use(express.bodyParser());
app.use(express.methodOverride());
app.use(express.cookieParser('your secret here'));
app.use(express.session());
app.use(app.router);
app.use(require('stylus').middleware(__dirname + '/public'));
app.use(express.static(path.join(__dirname, 'public')));
});

app.configure('development', function(){
  app.use(express.errorHandler());
});


app.get('/', routes.home);
app.get('/users', user.list);

http.createServer(app).listen(app.get('port'), function(){
  console.log("Express server listening on port " + app.get('port'));
});

In this way my var works, I can access environment.appName everywhere, but Y would have better solution

Thanks

IMHO global variables are a bad solution in gerneral. So there probably is no "clean solution" for a bad thing to do. — dave
– dave, Commented Nov 14, 2012 at 14:51
In the case of the Database connection (initialized at startup and only one object though the entire lifetime of the server) this is a good approach. — João Rocha da Silva
– João Rocha da Silva, Commented Nov 6, 2013 at 16:53
Glad you posted this, thanks... helped out a bit. Switching to node right now and trying to figure stuff out. Still not sure what the app.configure('development', function(){}); does even though I'm using it. Does that set the environment to development and then just comment that out when pushing to production? — BRogers
– BRogers, Commented Dec 8, 2013 at 22:59

xiaoyi · Accepted Answer · 2012-11-14 15:02:56Z

10

There is a global scope in node.js.

In the main file (the one you put behind node in command line,) all variables defined are in global scope.

var x = 100;
// which global.x === 100

And in other files loaded as module, the scope is not global but a local sandbox object, so you need global.x to access the same x in main file.

Seems it looks better than use a require().

answered Nov 14, 2012 at 15:02

xiaoyi

6,7611 gold badge36 silver badges54 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

thalisk Over a year ago

I believe you have to omit the var for it to be under the global object otherwise it's a variable of the scope of the module. Alternatively you can always be explicit by saying global.x = 100;

xiaoyi Over a year ago

@ThalisKalfigkopoulos Thanks for pointing out that. I assumed everyone read it could infer that from the context.

Collectives™ on Stack Overflow

Global variable express node.js

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related