Rename object with Node.js AWS S3 (copy object then delete object) with promises

aws-s3-rename.coffee

config = require 'config'
s3 = require 's3'
q = require 'q'

module.export = (oldKey, newKey) ->
  defer = q.defer()

  params =
    # you need to set the s3 bucket in the CopySource key
    CopySource: "#{ config.s3.bucket }/#{ oldKey }"
    Key: newKey
    
  s3.copyObject params, (err) ->
    if err then defer.reject(err) 
    else s3.deleteObject Key: oldKey, (err) ->
      if err then defer.reject(err)
      else defer.resolve()

  return defer.promise