CODEWITHSUNDEEP
javascriptnode.jscoffeescriptglobal-variables
krajol
krajol

Reputation: 848

Accessing global variables with node.js and CoffeeScript

I'm trying to declare global variables for my applications that I'm writing using Node.js and CoffeeScript. So I'm declaring it in a common file that is concatenated to both applications after compilation. In that file I have for example:

root = exports ? this
root.myVariable = 300

So my first application is a HTML one. When I try to access this variable, for example by 

console.log myVariable

There is no problem with it. But my other application is a server application lauched by node command and I cannot access that variable in that application. I tried:

console.log root.myVariable
console.log myVariable

With first line I'm getting 'undefined' printed (so it looks that root is defined) and with the second one, I'm getting ReferenceError - myVariable is undefined.

So how can I access this variable?

Here is an output code in Javascript that I get, I guess it might be helpful:

(function() {
  var root, _ref;

  root = (_ref = typeof module !== "undefined" && module !== null ? module.exports : void 0) != null ? _ref : this;

  root.myVariable = 300;

}).call(this);

(function() {

  console.log(root.myVariable);

  console.log(myVariable);

}).call(this);

Upvotes: 0

Views: 1101

Answers (2)

Mulan
Mulan

Reputation: 135197

You're close, but you need to change things just a little bit

# config.coffee
module.exports =
  foo: "bar"
  hello: "world"
  db:
    user: alice
    pass: password1

# lib/a.coffee
config = require "../config"

# lib/b.coffee
config = require "../config"

# lib/db.coffee
dbconfig = require("../config").db

Upvotes: 2

Leonid Beschastny
Leonid Beschastny

Reputation: 51450

Client and server JavaScript (or CoffeeScript) works differently. So, its a really difficult to write a module that'll work in both applications.

There is a lot of libraries to solve this problem, like RequireJS and Browserify.

But I have two simpler suggestions for your problem.

First one is to use JSON to store your global constants. On the server side you can simply require you JSON file:

root = require './config.json'

On the client side you may either parse it manually or serve it as pjson.

My second suggestion is to write really simple module that'll be compatible with both your applications. It'll look something like this:

root = 
  myVariable: 300
  myOtherVariable: 400

modulte.exports = root if module?.parent?

This code should be compatible with both node.js require function and browser <script> tag.

Update:

I just reread you question and realized, that you've did almost as I suggested. But your code looks fine to me. You may try to use module.export instead of its alias exports, it may help:

root = modulte?.exports ? this
root.myVariable = 300

But, as I said, your code looks fine to me as well.

Upvotes: 0

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