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Node.js and Modules require. Objects are not assigned by reference?

I'm writing this question after 2 days of total struggling during which I couldn't find a solution but also couldn't find an explanation of why this code is not working.
I will report a super simplified simulation of my code.
I have 5 Node.js files:
1) server.js -> Is the main file used to start the server
2) globalVars.js -> Is where all the server "global" objects are stored.
3) globalFunctions.js -> Is where all "general" functions are stored to be used by all other modules
4) helloManager.js -> Example file which contains some standard function used by the server
5) aspect.js -> Same as helloManager.js
//server.js
//Loading the globalVars file. All objects are passed by reference so I use this to store the global variables
var globalVars = require("./globalVars.js");
//Assigning to the respective global object all the functions exported from other modules
globalVars.Modules.globalFunctions = require("./globalFunctions.js");
globalVars.Modules.aspect = require("./aspect.js");
globalVars.Modules.helloManager = require("./helloManager.js");
//After this point, the objects in globalVars.js will be populated with the respective functions exported from the files
//A timeout just to be sure it is not a problem of timing? (Well, it is not...)
setTimeout(function(){
console.log(globalVars.Modules.helloManager.helloOutput());
}, 2000);
/*
Console will throw the following error:
../globalFunctions.js:6
return "MR. " + aspect.getAspect();
^
TypeError: aspect.getAspect is not a function
*/
//globalVars.js
//Objects that will be populated with the functions inside other modules
module.exports.Modules = {
aspect: {},
helloManager: {},
globalFunctions: {}
};
//helloManager.js
var globalVars = require("./globalVars.js");
var { globalFunctions } = globalVars.Modules;
module.exports.helloOutput = function(){
return "hello " + globalFunctions.getHumanData();
};
//aspect.js
module.exports.getAspect = function(){
return "human";
};
//globalFunctions.js
var globalVars = require("./globalVars.js");
var { aspect } = globalVars.Modules;
module.exports.getHumanData = function(){
return "MR. " + aspect.getAspect();
};
Please don't answer me to put everything in the same file, because my code is way more complicated to report so here I'm posting this very simple simulation.
I know that objects are assigned by reference and so if all modules get the variables from "globalVars" they works kinda like "global".
The problem is when in globalFunctions.js I load
var { aspect } = globalVars.Modules;
Since in server.js the module aspect.js is not loaded yet, it will be an empty object.
But I'm expecting that
var { aspect } = globalVars.Modules;
is getting the reference of globalVars and not a copy, so when server.js finishes loading all the modules, the variabile aspect inside globalVars.Modules will point to the correct object and so it would find the function I need!
Infact the console.log inside server.js is executed after all modules have been loaded for this exact reason.
Does anyone know what is the reason of this problem and how could I solve it?
Thank to everyone who will help!

What's happening
It's an issue of what it means to do const { aspect } = globalVars.Modules; (which is the same as const aspect = globalVars.Modules.aspect;). That is, it's a matter of assignment semantics.
Let's look at a simpler example, then we can see hot it applies to what you're doing. Assume you have:
let a = {/*original object*/};
When you do
b = a;
the value in a is copied into b. That value is an object reference, so they now both point to the same object, but there is no ongoing link between a and b. If you then do
a = {/*new object*/};
that has no effect whatsoever on b, because there's no ongoing link between a (the variable) and b (the variable). b still refers to the original object, not the new one.
The same is true of any assignable item, such as an object property or parameter. That's what's happening with globalVars.Modules.aspect. globalFunctions is grabbing the value (simple assignment semantics, though using destructuring), then server.js is replacing that value with a new one.
Here's how that's happening in your code:
// server.js
var globalVars = (function() {
// globalVars.js
return { // this is the `exports` object
Modules: {
aspect: {}, // *** That's the `a = {/*original object*/}`
}
};
})();
// back in server.js
globalVars.Modules.globalFunctions = (function() {
// globalFunctions.js
const { aspect } = globalVars.Modules; // **** That's the `b = a`
return { // this is the `exports` object
getHumanData: function(){
return "MR. " + aspect.getAspect();
}
};
})();
// back in server.js
globalVars.Modules.aspect = (function() { // *** that's the `a = {/*new object*/}
return { // this is the `exports` object
getAspect: function(){
return "human";
}
};
})();
// back in server.js
globalVars.Modules.globalFunctions.getHumanData(); // Fails because the object it's using
// is the old one, not the new one
How to fix it
globalFunctions.js relies on aspect.js, so have it rely on it directly:
// In `globalFunctions.js`
const aspect = require("./aspect.js");
module.exports.getHumanData = function(){
return "MR. " + aspect.getAspect();
};
Assuming there are no cycles, that'll work.
At a larger level: There may be no reason to have globalVars.Modules at all. A module is only loaded once (normally), so rather than globalVars.Modules, just have each module directly rely on the module it needs, rather than funnelling it all through a central object. Node.js' module cache is already the central object.
If you don't want globalFunctions.js to rely on aspect.js directly (why not?), then don't copy the aspect property from Modules, use it as of when you need it:
// In `globalFunctions.js`
const {Modules} = require("./globalVars.js");
module.exports.getHumanData = function(){
return "MR. " + Modules.aspect.getAspect();
};
That'll work assuming nothing reassigns Modules (which nothing seems to in the code you've shown). But again, it makes more sense to rely on aspect.js directly if you can.
It's kind of fun to note that this is one of the reasons that modern ESM modules don't use simple assignment semantics like CommonJS ones do. ESM wouldn't help your specific thing, because you're using your own globalVars.Modules object instead of using the module objects, but it solves a problem that people often had with CommonJS modules which, like your problem, was caused by expecting b (an imported value) to be affected when reassigning a (the exported value). The issue people would have with CommonJS happened mostly when there were cycles between two modules (circular dependencies, directly or indirectly). ESM solves this by making the imported binding (b in my example) a live binding to the exported binding (a in my example). This is the only place JavaScript has what you could argue is a form of pass-by-reference (references to variables).

As you've noticed, var { aspect } = globalVars.Modules; copies the current value of globalVars.Modules.aspect to the local variable aspect. It's just alternative syntax for var aspect = globalVars.Modules.aspect.
If you later change the value of globalVars.Modules.aspect to a new object (as opposed to mutating the object that is already there) then the local variable doesn't update.
If you want the most recent value then you need to continue accessing globalVars.Modules.aspect whenever you need it.

I cannot access the variable in the other script. (Module.exports don't work everywhere)

I have been having issues with module.exports.
I have 2 Scripts that use Discord.js, and i need to have a SetTimeout() variable that is common to both scripts to be able to use ClearTimeout() from each of them.
I tried to use:
//first script
var foo = 20;
module.exports.foo = foo;
//Second Script
var exp = require('./firstscript');
console.log(exp.foo);
This was a test, to see if i was doing it the wrong way, with a simple variable instead of my SetTimeout().
The test worked fine when i ran new scripts with the node command but with npm start on my 2 original scripts it returned 'undefined' while having the same syntax.
In every script is already a module.exports for the Discord.js event class like 'Ready' for exemple.
I'm running this bit of code outside the main module.exports at the top where the const are declared.
I wonder if this is causing my issue.
example:
//the code i'm talking about is here.
module.exports = class ReadyEvent extends BaseEvent {
constructor() {
super('ready');
}
async run(client) {
Thanks for your help. Ask me for clarification if needed.
EDIT:
I looked up on the internet to see if it was an issue with the module.export that was already present on the script. And it was.
Apparently you cannot have several module.export in a script if each one of them doesn't specify a variable:
//this doesn't work
module.exports.value = value;
module.exports = value2;
//this works
module.exports.value = value;
module.exportd.value2 = value2;
My problem was that the one already present was used by the 'discord.js compiler' to register every command so i couldn't modify it without breaking the bot.
I decided to put my timer in a new script named GlobalVars and it worked Perfectly fine.
I'm Satisfied that it works now. For me the issue is fixed but i would love to know if it is possible to export a variable WITH the discord.js module.exports syntax included.

From your Second Script variable, its seems to be requiring a folder and not a file, and I don't think folders are allowed.
Assuming you are requiring a script and not a folder:
First Mistake: When requiring, inside the brackets you must have quotation marks ("") or ('').
If it is a folder, add a / next to ./firstscript and assign it to the file you want to refer to.
var exp = require('./firstscript/THE_INTENDED_FILE');
...If firstscript is a json file:
var exp = require('./firstscript.json');
Extracting Variables from file
// Option 1:
console.log(exp.foo);
// Option 2:
const extract = exp.foo
console.log(extract);

Node define unique variable that I need to use across the modules

Currently I am just passing my fileNamePrefix like that:
let shortid = require('shortid');
let fileNamePrefix = shortid.generate();
module1.run(fileNamePrefix); //generating a file based on `fileNamePrefix` `xxxxx.f1.json`
module2.run(fileNamePrefix); //generating a file based on `fileNamePrefix` `xxxxx.f2.json`
module3.run(fileNamePrefix); //generating a file based on `fileNamePrefix` `xxxxx.f3.js
Which I think in not quite right, I might need to pass more things to my modules later on, so I want to avoid to pass that as function params.
What is the best way to approach that in nodejs?
Will global object like global.fileNamePrefix = shortid.generate(); will do in that case or would you approach that different? I just read that global is not good...

You can use either singleton approach or approach suggested by #Сергей Тертичный
Singleton :
//shortid.js
var fileSingleTon = module.exports = {
fileNamePrefix: null,
getFileNamePrefix: function() {
return fileSingleTon.fileNamePrefix || fileSingleTon.generate()
},
generate: function() {
console.log('generating..');
return fileSingleTon.fileNamePrefix = 'your_file_prefix';
}
}
//module1.js
var fileNamePrefix = require('./shortid').getFileNamePrefix();
//do stuff for module1
//module2/js
var fileNamePrefix = require('./shortid').getFileNamePrefix();
//do stuff for module1
and so on..
Even now you are calling require('./shortid').getFileNamePrefix(); multiple times, generate function is getting called only once.
Node Caching approach :
Consider you have shortid.js as following :
// A: block of code to do some manipulations
// B : module.exports = manipulation result.
So basically in node js "modules" core module which is responsible for giving us module.export functionality executes whatever is here above export(in abode example the part A) only for the first time and caches it even if you have required in in multiple other files. However, it only executes the functions or block of code in every require which is inside export. So you can use this approach where your A block will have login to generate fileNamePrefix and then B just returns it.

Just create module like that:
// unicname.js
let shortid = require('shortid');
let fileName = shortid.generate();
module.exports = {fname: fileName};
//module1.js
const {fname} = require('./unicname.js');
....
Since the node.js caching the modules the value will be calculated only one time so you can get same value in all your modules.

Babel not compiling global variable

I'm missing the var declaration when coding. I have preset-0 and transform-runtime installed. The console shows the following error:
key is not defined
This is the code I'm running:
let set = new WeakSet();
key = {}; // missing var
set.add(key);
console.log(set.has(key));
But when I added the var keyword everything is fine:
let set = new WeakSet();
var key = {}; // added var
set.add(key);
console.log(set.has(key));
The console outputs:
true
Which means I cannot create global variables at will with babel?

Not like that you cannot.
You can always assign variables to the window.MyKey = whateverValue from any file and access this value from any other file in your app. But that's not the best way to share data globally in your app.
Best approach would be to create a file, say MyFile.js
class MyFile {
constructor() {
this.MyKey = 10;
}
}
export default (new MyFile);
Now you can require this file anywhere in your app and access the same instance of MyFile. So,
randomFile.js
import MyFile from './MyFile'
MyFile.MyKey = 20;
This approach avoids polluting the global scope but you accomplish the same functionality.

Can't access module object properties from main in Screeps

I have the following simple test module (called testModule) in Screeps:
module.Exports = {
myProperty:'test'
};
In main, I try to output the contents of the module like so:
var x = require('testModule');
console.log("Value:" + JSON.stringify(x));
But all I get is an empty object ({});
As a result, x.myProperty is undefined. I have also tried making the module into a function, like so:
module.Exports = function(){
return {
myProperty:'test'
};
};
Then assigning it to x with var x = require('testModule')(); but I get the same result.
Obviously the game is still in development, so it is possible that this is a bug, but I'd like to rule out a mistake on my part first. Anyone been able to achieve what I'm trying to do? Anyone see what I'm doing wrong?
Edit
Interestingly, it gives me the same empty object even if I change the module to this:
module.Exports = 'test';
Surely this should be printing the string 'test' rather than an empty object? Is this a quirk of require js?

Just figured this out - I was using an uppercase E in module.exports. I have corrected the case and now it works fine:
module.exports = {
myProperty:'test'
};