NodeJS- ReferenceError: wagner is not defined - node.js

Question

I don't have experience at all with nodejs and I am learning. I have a code, which I am testing and giving me the following errors, and I don't understand why:
1) Part 3 Assessment Tests "before all" hook:
ReferenceError: wagner is not defined
at Object. (fx.js:2:31)
at Object. (dependencies.js:3:10)
at Context. (test.js:29:20)
2) Part 3 Assessment Tests "after all" hook:
TypeError: Cannot read property 'close' of undefined
at Context. (test.js:65:11)
These are the programs involved in the issue:
test.js --------------
var assert = require('assert');
var express = require('express');
var fs = require('fs');
var status = require('http-status');
var superagent = require('superagent');
var wagner = require('wagner-core');
var URL_ROOT = 'http://localhost:3000';
var PRODUCT_ID = '000000000000000000000001';
describe('Part 3 Assessment Tests', function() {
var server;
var app;
var succeeded = 0;
var finalCharge;
var Category;
var Config;
var fx;
var Product;
var Stripe;
var User;
before(function() {
app = express();
// Bootstrap server
models = require('./models')(wagner);
dependencies = require('./dependencies')(wagner);
// Make models available in tests
var deps = wagner.invoke(function(Category, fx, Product, Stripe, User, Config) {
return {
Category: Category,
fx: fx,
Product: Product,
Stripe: Stripe,
User: User,
Config: Config
};
});
...
dependencies.js -------------
var wagner = require('wagner-core');
var fs = require('fs');
var fx = require('./fx')(wagner);
var Stripe = require('stripe');
module.exports = function(wagner) {
var stripe =
// TODO: Make Stripe depend on the Config service and use its `stripeKey`
// property to get the Stripe API key.
wagner.factory('Stripe', function() {
return Stripe(Config.stripeKey);
});
wagner.factory('fx', fx);
wagner.factory('Config', function() {
return JSON.parse(fs.readFileSync('./config.json').toString());
});
var Config = wagner.invoke(function(Config) {
return Config;
});
};
fx.js --------------------------
var superagent = require('superagent');
var _ = require('underscore')(wagner);
module.exports = function(Config) {
...
};
I think I shouldn't have any problem because wagner is defined on test.js and passed as parameter to dependencies.js, and it is passing it on to fx.js.
1- Could you tell me what is wrong in the code ?
2- The second error, I have not cue why is it happening.
Please, help

Answer 1

In your dependencies.js, in the fx definition, you dont need to pass wagner as parameter, because that variable doesnt exist there:
var fx = require('./fx');
As i see, you already defined the Config factory, and you dont need to assign it to a variable for use it, because wagner will autoinject your "Config" factory, allowing you access to it:
wagner.factory('Stripe', function(Config) {
return Stripe(Config.stripeKey);
});
...
wagner.factory('Config', function() {
return JSON.parse(fs.readFileSync('./config.json').toString());
});
Then in your fx.js, when you wanna use the Config parameter you just pass it:
module.exports = function(Config) {
var url = 'http://openexchangerates.org/api/latest.json?app_id=' +
Config.openExchangeRatesKey;
...
}
Exactly the same you should do if you wanna use the "Config" factory in any other file:
[auth.js]
function setupAuth(User, Config, app) {
...
}

Answer 2

You're trying to use wagner in fx.js before you execute the exported function and outside of the scope that wagner is passed to. Also, Config seems a bit misleading if you're passing wagner to that function instead.
If you can defer loading underscore, you could do something like:
var superagent = require('superagent');
var _;
module.exports = function(Config) {
if (!_)
_ = require('underscore')(Config);
// ...
};