Can I use CoffeeScript instead of JS for node.js?

Question

What are my restrictions if I want to code node.js and use CoffeeScript? Can I do anything I'd be able to do in JS?

Answer 1

Try this

#!/usr/bin/env coffee
v = 78
console.log "The value of v is '#{v}'"

Then do:

chmod +x demo.coffee
./demo.coffee

CoffeeScript has pretty solid integration with node. Once the 'coffee-script' module is loaded, either by require('coffee-script'), by the she-bang I demo'd above, or by running coffee demo.coffee ... once loaded, you can used require('./foo') to bring in foo.coffee

Answer 2

If you want to automatically compile all your coffeescript files (in one directory including subdir) every time they change into javascript, just use this command:

find . -name '*.coffee' -type f -print0 | xargs -0 coffee -wc

Answer 3

Yes, CoffeeScript simply compiles into pure JS, making it completely compatible with node.js.

To run CoffeeScripts on node, you can either:

• Type coffee -c example.coffee to compile, followed by node example.js to run the compiled JS.
• Simply type coffee example.coffee

Answer 4

Yes, here's a different & simpler answer. You need to do 2 steps.

1. npm install coffee-script --save # I assume you would have done this already.

2. Have require('coffee-script') as the first line that would get executed in server.js of app.js. (UPDATE: since coffee script 1.7, you will have to do require('coffee-script/register'))

This registers coffeescript compiler to your app and you can start treating coffee files and js files equally now (meaning that you can require coffee files too !).

This method will require you to write just the one file (app.js) in vanilla javascript. But the advantage is that your deploy environment need not have coffeescript as an initial globally installed dependency to run your app. In this case, you would just have to copy over your code, and npm install would install all packages necessary. And npm start would have you up and running

Answer 5

Video Tutorials

I've seen a great tutorial series by Pedro Teixeira. He's been building an entire series on node tutorials. He includes reference to nodemon for auto detection and compilation and reloading of edited .coffee files.

1. Coffeescript and Node.js
2. Nodemon

Answer 6

Not only can you run CoffeeScript files directly in Node with

coffee source.coffee

you can also require them as if they were JavaScript files. For instance, if you have lib.coffee in a directory, you can write

require './lib'

from another CoffeeScript file in the same directory. (In order to do this from a JavaScript file, you'll have to add require 'coffee-script' at the top.) So, you never have to do compilation explicitly under Node, unless you're packaging your project for deployment with a tool like npm.

One caveat: In stack traces, the line numbers you'll see refer to the compiled JavaScript, even when you're running CoffeeScript directly (so you don't have access to the JavaScript). A lot of folks are trying to fix this, but it's a big challenge.