Get started with Backbone and CoffeeScript

Question

I think this is more of a CoffeeScript question. I want to be able to use classes from Backbone in a foo.coffee file. I tried using the -r option to require Backbone when running the coffee command:

coffee -r "../backbone" -c foo.coffee

The compiler complained that Backbone was undefined. I'm sure that this must be pretty simple. It's easy to find examples of people using CoffeeScript and Backbone together. I also tried requiring the class at the top of the file like so:

Backbone.model = require('../../backbone').Model

class foo extends Backbone.model

I could write it to console.log in the initialize method. When I tried writing this to console.log, I just got an empty object {}.

Can anyone tell me how to get this going?

Answer 1

Could you provide more of your code? I wasn't able to replicate the issue you had with initialize. Here's my code, with backbone.js in the same directory as the coffee file:

Backbone = require './backbone'

class foo extends Backbone.Model
  initialize: ->
    console.log this

new foo

On new foo, initialize is called and the output is

{ attributes: {},
  _escapedAttributes: {},
  cid: 'c0',
  _previousAttributes: {} }

As to the issue with -r, there are two reasons it doesn't work: First, -r performs

require '../backbone'

without assigning it to anything. Since Backbone doesn't create globals (only exports), the module has to be assigned when it's required.

Second, using -r in conjunction with -c doesn't add the required library to the compiled output. Instead, it requires it during compilation. Really, -r only exists so that you can extend the compiler itself—for instance, adding a preprocessor or postprocessor to the compilation pipeline—as documented on the wiki.

Answer 2

If you're using CoffeeScript and Backbone.js, I recommend checking out Brunch. It may just get you past your difficulties.