organic-plasma-feedback

organic-plasma-feedback v2.0.0

Provide syntax sugar on top of organic-plasma implementations with feedback support.

usage

var Plasma = require('organic-plasma')
var plasma = require('organic-plasma-feedback")(new Plasma())

plasma.on('chemical1', function (c, callback) {
  // do work
  callback(err, {success: true})
})

plasma.emit('chemical1', function (err, result) {
  // result.success === true
})

API

All results from reactions for callback invoke are delivered as chemicals via plasma having the following signature:

{
  type: chemical.type + '-result',
  err: Error,
  result: Primitive,
  $feedback_timestamp: Date
}

plasma.on(pattern, handler, context, once)

arguments

• pattern - the pattern on which to listen for chemicals
  • as String - matches against the Chemical.type property
  • as Object - matches against one or more properties of Chemical
• handler - Function Invoked when a chemical, matching the pattern has been emitted. Invoked with:
  • c - Object emited Chemical
  • callback - Function (optional) - function (err, result), called to return feedback on the emited chemical. Can be omitted to and the plasma.on
• context - Object (optional) - the context used when invoking the handler function
• once - Boolean (optional) - indicates whether only one chemical will be processed by the handler function. After the chemical is processed the handler is unregistered

Callback usage - plasma.on(pattern, function (c, callback){} [, context][, once])

Registers a function to be triggered when a chemical emitted in the plasma matches the given pattern.

plasma.on("test-chemical", function (c, callback){
  // do some processing with `c`
  callback(null, { success: true })
}, undefined, true)

plasma.emit(c, callback)

Immediately triggers any reactions matching the given c chemical and provides feedback support via callbacks.

arguments

• c - Object - to be emmited with the Chemical structure
  • as String - equals to { type: String, ... } Chemical
  • as Object - must follow the Chemical structure
• callback - Function - function (err, result) {}

plasma.emit({ type: 'test' }, function (err, result) {})
plasma.emit('test', function (err, result) {})

Feedback examples

emit and receive callback from the first who respond

plasma.on({type: 'c1'}, function (c, callback) {
  callback(err, 'result1')
})
plasma.once({type: 'c1'}, function (c, callback) {
  callback(err, 'result2')
})

var c = {type: 'c1'}
plasma.emit(c, function callback (err, result) {
  // callback will be invoked just once with result === 'result1'
})

emit and receive callback invocation from all who respond

plasma.on({type: 'c1'}, function (c, callback) {
  callback(null, 'result1')
})
plasma.on({type: 'c1'}, function (c, callback) {
  callback(null, 'result2')
})

var c = {type: 'c1', $feedback_timestamp: 'unique-timestamp'}
plasma.emit(c, function callback (err, result) {
  // 1st callback invoke result === 'result1'
  // 2nd callback invoke result === 'result2'
})

Performance notice

This implementation is ~6 times slower than organic-plasma v0.0.7, however it provides greater control over plasma's feedback support and is aligned to its pattern in nature.