evie

Evie

Install

npm install evie

Using the provided class

{Evie} = require "evie"

events = new Evie()

Creating your own class with Evie as a mixin

{evie} = require "evie"

class MyEvents extends EventEmitter
  evie(@)

events = new MyEvents()

What Evie can do

Evie (and any class that has been evied) provides several useful methods, many of which rely on following a convention for the names of emitted events. For error conditions, emit an event named "error". For successes, emit "success".

events = new Evie()
if everything_wrong?
  events.emit "error", new Error "It is all wrong"
else
  events.emit "success", {everything: "ok"}

Other event names are certainly legal, but they are not used by the serially, concurrently, and wrap methods.

forward and source

The forward method relays all events from one instance to another. source creates a new instance and forwards all events from it to the caller. This allows events to bubble up through a tree, which can be useful in observing and handling errors at a single place in your system.

base = new Evie()
base.on "error", (error) -> console.error "We have a problem:", error

stuff = ->
  base.source (events) ->
    number = Date.now()
    if number % 7 == 0
      events.emit "error", new Error "Oh no, the time is divisible by seven!"
    else
      events.emit "success", number

e1 = stuff()
e1.on "success", (result) ->
  console.log "The time is #{result} and it is NOT divisible by 7"

e2 = stuff()
e2.on "success", (result) ->
  console.log "The time is STILL not divisible by 7."

wrap

serially

concurrently