require

const fs = require('fs-extra');

Require avaliable everywhere

Runs the file

Where It Looks

Looks in core modules, then/or all paths specified by module.paths in order which is basically potentially every node_modules folder from curfolder to root

Looks for .js then .json then .node

.js in string is optional

Folders

If don't want to just look in node_modules can use paths

const config = require('./config');

Works whether a config folder with an index.js or config.js in the current folder

To change main folder, can add package.json to config folder with "main": "start.js" and it looks at start.js

What does require return?

Recall module is something defined for each file

require returns the module.exports object

So in config.js

function myFunction() {
    console.log("HEYYYYY");
}

module.exports = myFunction;

Then in other file

const config = require('./config')

config();

Circular?

Returns partially loaded module.exports so it can finish

Can I only execute code if I run this file?

Yes!

if (require.main === module) {
  // The file is being executed directly (not with require)
}

how to get args though?

process.argv[2], process.argv[3]

process.argv[1] is the filename