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Apparat = class
nextId: -> @_nextId++
constructor: ->
@_eventCallbacks = {}
@_failed = false
@_nextId = 1
debug: (@_debugCallback) =>
@_debugCallback 'debugCallback registered'
_debug: (message) =>
if @_debugCallback?
@_debugCallback message
onError: (onError) =>
unless typeof onError is 'function'
throw new TypeError """
first argument must be a function"
but is #{typeof onError}
@_onError = onError
@_debug 'onError callback registered'
receive: (args...) =>
# preconditions
if @_failed
throw new Error """
receive called on failed instance
argc = args.length
if argc < 2
throw new Error "at least two arguments are required"
cb = args[argc-1]
unless typeof cb is 'function'
throw new TypeError """
last argument must be function
but is #{typeof cb}
events = args[0...argc-1]
events.forEach (event, index) ->
unless typeof event is 'string'
throw new TypeError """
event argument #{index} must be string
but is #{typeof event}
id = @nextId()
received = []
receivedCount = 0
events.forEach (event, index) =>
@_eventCallbacks[event] ?= []
@_eventCallbacks[event].push (result) =>
received[index] = result
if receivedCount is events.length
@_debug "##{id} receiving [#{events.join ', '}]"
cb received...
@_debug "##{id} receiver for [#{events.join ', '}]"
send: (event) =>
unless typeof event is 'string'
throw new TypeError """
event must be string
but is #{typeof event}
if @_failed
throw new Error """
send called on failed apparat
if @_eventCallbacks[event] is false
throw new Error """
[#{event}] trying to register sender but event was already sent
id = @nextId()
called = false
cb = (err, result) =>
if @_failed
@_debug "failed apparat: not forwarding [#{event}]"
if called
throw new Error "sender ##{id} called twice"
called = true
if @_eventCallbacks[event] is false
throw new Error "[#{event}] already sent"
if err?
@_debug "##{id} sending [#{event}] ✖"
@_failed = true
if not @_onError?
throw new Error """
send for "#{event}" failed with "#{err}"
but no onError callback was registered
@_onError err
@_debug "##{id} sending [#{event}] ✔"
callbacks = @_eventCallbacks[event]
if not callbacks?
throw new Error """
"#{event}" was sent
but no callbacks were found
callbacks.forEach (cb) -> cb result
# mark event as sent
@_eventCallbacks[event] = false
# TODO nextTick??
@_debug "##{id} sender for [#{event}]"
return cb
module.exports = -> new Apparat
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