title: 3 JavaScript files talking to each other
body: <p>How can 3 separate JavaScript files "talk to each other" outside of a browser? Can someone expound on how these 3 different JS files can use each other's code? How to avoid circular dependencies, etc?</p>
  
  <p>foo.js
  bar.js
  mud.js</p>
  
  <p>I know there are things like "var foo = require(./foo.js)" and "module.exports" but right now it's not making much sense.</p>