Writing a Coffeescript App



For this tutorial, we’ll show you how to create and run a CoffeeScript project, entirely within the Cloud9 IDE. To run any coffeescript project, you’ll need to first make sure to install the coffeescript module via the Node Package Manager (npm). We’re going to walk you through how to do that with a sample project.

First, create a new project. Then, in the console, enter the following command:

git clone git://github.com/fjakobs/cloud9-coffeescript-example.git

This is a sample CoffeeScript application written by one of our developers. After cloning the project, you’ll find three different files in the project tree: server.js, app.coffee, and README.md.

The README.md file contains instructions to install coffee-script using npm. We’ve integrated Node Package Manager into Cloud9 IDE to enable users to install Node programs. Thus, from the Cloud9 IDE command line, type the following command to install the Coffeescript module:

npm install coffee-script

Next, let’s have a look at the server.js file. The first line is the require() function, which is used to load the coffee-script module that you have just installed. On the second line, we declare the CoffeeScript file that contains your application. In the last line, we specify the port the server is listening to. When projects run within Cloud9 IDE, you must retrieve the port information using process.env.PORT.

Now, let’s look at what the CoffeeScript file does. It creates an HTTP server with a function that is called for each request. In the callback function, you create a response with a status code of 200 (indicating that the request was fulfilled successfully) and the message “Hello World”. You use module.exports to enable the server.js file to use the code in the CoffeeScript file:

http = require "http"

module.exports = http.createServer
((req, res)
   res.writeHead 200, 'Content-Type': 'text/plain'
   res.end 'Hello World\n'

Next, run the server.js file and open the URL indicated in the console:

The result is:

To stop your application, go back to the editor and click on the stop button in the Menu Bar.

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