Simple promises example

promises.coffee

Q = require 'q'
 
receivePromise = (func) ->
  (args...) -> Q.spread args, func
 
returnPromise = (func) ->
  (args...) ->
    deferred = Q.defer()
    args.push (val) -> deferred.resolve val
    func args...
    deferred.promise
 
add = receivePromise returnPromise (a, b, cb) -> setTimeout (-> cb a + b), 3000
multiply = receivePromise returnPromise (a, b, cb) -> setTimeout (-> cb a * b), 3000
 
print = receivePromise (val) -> console.dir val
 
result  = add 4, 4
result2 = multiply result, 10
print result2