I’ve always liked the idea of being able to reuse Javascript code in both Node.js (on the backend) and the browser (on the frontend). I finally ran into a situation this weekend where it was practical to do this and I was surprised by just how easy it was to do. I thought I’d throw my solution into a post. The code below is written in CoffeeScript.
# Define my class
class myClass
# Define a method within my class
doSomething: ->
console.log("Hello world!")
# Add to exports for node, or window for browser
if typeof module isnt 'undefined' and module.exports
module.exports = new myClass()
else
this.myClass = new myClass()
First, we create a class named "myClass" and add a method to it. Then, with a simple if statement, we can determine whether we’re running this code in Node.js or in the browser and export the class accordingly. Let’s assume we’re compiling this down into "my-class.js".
In Node.js, we would use the class like this:
myClass = require("my-class")
myClass.doSomething()
In the browser, we would use the class like this:
<script type="text/javascript" src="my-class.js"></script> <script type="text/javascript"> window.myClass.doSomething() </script>