Nodejs: Global variables across multiple files

Question

I have written my code across several files for my node server.

If I have a file, say basket.js:

var Basket = {
    fruits : 0,
    
    addFruit : function() {
        fruits++;
    },

    removeFruit : function() {
        fruits--;
    },

    printFruit : function() {
        console.log(this.fruits);
    }
}
module.export = Basket;

And I have another file called give.js:

var Basket1 = require("./basket.js");

Basket1.addFruit();
Basket1.printFruit();

And another file called take.js:

var Basket2 = require("./basket.js");

Basket2.removeFruit();
Basket2.printFruit();

Will both files write into the same instance of Basket? In other words, will they both have control over the property, fruits? Does node manage race conditions on its own? i.e. if two commands to modify fruit come in at the same time from add and sub, does node know how to handle it?

If I want to make a way in which two files can look at a singleton at the same time and access it, is this the way to go?? Or how else does one do it?

When I try out the above code, it does'nt work... it creates a new instance of Basket every time i run removeFruit or printFruit... — user3794529, Jul 29 '14 at 14:40
You may want to take a look at this [another answer](http://stackoverflow.com/a/24292207/697630). — Edwin Dalorzo, Jul 29 '14 at 19:19

score 5 · Accepted Answer · edited Jun 20 '20 at 09:12

Yes, they will access the same object.

Modules are cached after the first time they are loaded. This means (among other things) that every call to require('foo') will get exactly the same object returned, if it would resolve to the same file.

– Modules docs

No, node does not manage race conditions on its own, because race conditions will not be caused by node itself. Node is single-threaded and thus no code can be executed at the same time as other code. See for example this answer for some more explanation.

score 2 · Answer 2 · edited Jan 08 '16 at 23:37

2

I'm a beginner but I think the correct syntax is module.exports not modules.export - if you may correct so that people don't wonder why it does not work like I just did :)

edited Jan 08 '16 at 23:37

Manos Nikolaidis

21,608
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answered Jan 08 '16 at 23:29

GBill

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3

Nodejs: Global variables across multiple files

2 Answers2