Exports vs Module.Exports (Node)

Edit: I'm prepending here a little section on another system of imports and exports.

This post is about imports/exports in Node. Another way to think about it is, if you run the command node file.js then you'll need to use the const my_const = require('./some_file') convention below.

But if you're running a non-node library like React, you'll import a little differently. The required import/export statements for these situations are described adequately in the MDN docs.

Ok back to our regularly scheduled content

We stared using Node last week, and as I wrote in an earlier post, it works a bit differently from the JS environment in-browser. Notably, the way files interact and gain access to each others' properties (this is a sentence fragment but feels right anyway).

In an earlier sprint, we used module.exports so that one file could allow another file to access its functions and variables. In our current sprint, one of our boilerplate project files uses exports instead. What's the difference?

The answer to this question unfolded only after really careful study and many late nights working by candlelight. Read on only if you're ready to embark on a similar journey.

Exports IS Module.Exports

That's it. That's the answer. No more journey.

Here I'll show you.

//anyFile.js

console.log(module.exports === exports)
>>true

True! Mystery solved.

So with that, why are they both used? Why does out boilerplate code use module.exports in some cases and exports in another?

I'm not sure! But what's important now is that I have a working knowledge of this tool, and that's exactly what I was looking for. I did come across some references to cases where other developers have reassigned exports to other objects, but you know what we call those references? Rabbit holes.

Can I use exports? Yes. Can I use module.exports? Yes. Is that good enough to continue with my work? Yes.

Ok so what is module.exports?

If you want a really nice explanation, read here: https://www.freecodecamp.org/news/require-module-in-node-js-everything-about-module-require-ccccd3ad383/.

If you like demos, I've got you covered.

Let's take two files in the same directory: exporter.js and importer.js:

\\exporter.js

var demoFunc = function(){
  console.log('it works!')
}

var demoVar = 'learning is FUNdamental'

module.exports.demoVar = demoVar
module.exports.demoFunc = demoFunc

\\importer.js

const imported = require('./exporter.js');

console.log(imported.demoVar)
imported.demoFunc()

>learning is FUNdamental
>it works!

What happens is that the module.exports objects in exporter.js is made available directly by require('./exporter.js') in importer.js.

You can think of it like this:

require('./exporter.js'); = module.exports.

So if we assign WHATEVER like so: module.exports.whatever,

then that is available in another file like so: require('./exporter.js').WHATEVER.

And if we set that 'require' statement to a variable: const demo = require('./exporter.js')

then we can now access our property via: demo.WHATEVER.