coffeescript - Curly Braces when Extending Node.js Class -

why wrap our variables in curly braces, {eventemitter} = require 'events', when extending node.js class?

for example, trevor burnham, in tutorial on event-driven coffeescript, extends node's eventemitter way:

{eventemitter} = require 'events'  class rooster extends eventemitter   constructor: ->     @on 'wake', -> console.log 'cockadoodledoo!'  (foghorn = new rooster).emit 'wake' # cockadoodledoo! 

this:

{eventemitter} = require 'events' 

is equivalent javascript:

var eventemitter; eventemitter = require('events').eventemitter; 

when require 'events', you're getting object module's exports, 1 of exports eventemitter "class". using {eventemitter} idiomatic shortcut pulling eventemitter out of object require 'events' returns; this:

eventemitter = require('events').eventemitter 

if prefer. braced version starts come in handy when want extract more 1 part of object; example, this:

{a, b} = c 

is javascript:

var a, b; = c.a; b = c.b; 

the destructuring assignment section of coffeescript documentation might make reading right now.