handler error in `iced-coffee-script`

_z_example.iced

fs = require 'fs'


_z = (errcb, cb)->
  return ()->
    return errcb.apply null, arguments if arguments[0]
    return cb.apply null, arguments

myfunc = (handler) -> # like `app.get '/', (req, res, next)->` in `express`
  handler 'dummy1', 'dummy2', 'dummy3', 'dummy4', (err, data)->
    return console.error err.stack if err
    console.log data if data
 
myfunc (param1, param2, param3, param4, next)->


  await fs.readFile param1, 'utf8', _z next, defer err, data
  console.log "Data: #{data}"
  
  await fs.readFile param2, 'utf8', _z next, defer err, data
  console.log "Data: #{data}"
  
  await fs.readFile param3, 'utf8', _z next, defer err, data
  console.log "Data: #{data}"
  
  await fs.readFile param4, 'utf8', _z next, defer err, data
  console.log "Data: #{data}"

  console.log 'complete'

@xinyu198736