Create constants correctly with Mean.js (Node js)

Question

I’m starting to study Mean.js and I was in doubt when the best way to create my application constants. I need to store some constants in the project to be accessible in various parts of the code.

Searching, I found nothing related to constants in the documentation of Mean.js.. On the web, I found these references right here in stackoverflow.

https://stackoverflow.com/questions/15881665/how-to-define-a-constant-and-access-it-everywhere-in-nodejs

https://stackoverflow.com/questions/8595509/how-do-you-share-constants-in-nodejs-modules

Specifically on the second link I found Dominic Barnes' reply very elegant, but in the specific case of Mean.js there is still an abstraction of modules to consider (Mongoose).

How could I create my constants without interfering with the functioning of Mongoose (and without getting ugly, preferably =) )

Note: one thing I would like is that each module file keeps its own constant, so a model of Cars for example, would have the constant

Cars.CARRO_DE_PASEIO

That could have a string, object etc (I’d settle for a string hehe). Something like this...

Answer 1

In the Nodejs there is global which is a global variable. Similarly window in javascript in browser.

So it is possible to add properties to global and use them wherever you want. You should use them for example global.minhasConstantes = {}; and in that object add key-value to each constant, and not add new constants directly global.constanteA = 'foo'; global.constanteB = 'bar'; for the sake of good practice.

However what I usually do is define the variables when I call the modules. Examples:

in index.js

var modulo = require('modulo')(minhaConstante);

and in the module:

module.exports = function(k){
    return function(){
       // aqui fica o códigoque precisa da constante "k" que é passada para o escopo da função
    }
}

or only:

module.exports = function(k, outroParametro){
   // aqui fica o códigoque precisa da constante "k" que é passada para o escopo da função
}