Weak-emitter NPM

weak-emitter

Contexts based event emitter on ES6 WeakMaps

const context = {}
const eventKey = 'propName'
emitter.on(context, eventKey, (...args) => console.log(args))
emitter.emit(context, eventKey, 'first', 2, true)
// ['first', 2, true]

Install

npm i weak-emitter --save
# or: yarn add weak-emitter

Emitter API

Argument types:

context: object
eventKey: string | object
handler: (...args: []) => void

on(context, eventKey, handler)

Create new event with eventKey in context that will trigger the handler. Every handler will be added once, despite the number of times it was added to the event. Handlers are invoked in the order they were added.

Returns an event controller that has three methods:

emit(...args): trigger handler
off(): remove event
tranfer(destination): moves the event to destination context

const context = {}
const eventKey = 'propName'
const evController = emitter.on(context, eventKey, (...args) => doSomething(args))

const ctx2 = {}
evController.transfer(ctx2)
evController.off()

emit(context, eventKey, ...args)

Invoke all handlers in context tagged with key, passing the rest of the arguments

const context = {}
const eventKey = 'propName'
emitter.on(context, eventKey, (...args) => console.log(args))
emitter.emit(context, eventKey, 'first', 2, true)
// ['first', 2, true]