Reactive Object using getters + setters

reactive_object.coffee

# pretty straightforward, very similar to the Session object, except uses getters and setters
# to allow reactivity to happen 'magically'
class ReactiveObject
  constructor: (attributes) -> 
    @attributes = attributes
    @contexts = {}
    
    _.each attributes, (v, key) =>
      @contexts[key] = {}
      Object.defineProperty(this, key, 
        get: -> 
          ctx = Meteor.deps.Context.current
          @contexts[key][ctx.id] = ctx if ctx and not (ctx.id in @contexts[key])
          @attributes[key]
        set: (value) -> 
          context.invalidate() for k, context of @contexts[key]
          @contexts[key] = {}
          @attributes[key] = value
      )