Delightful bus

Event bus with more features

Installation

$ yarn add delightful-bus

import Eventbus from "delightful-bus"

const bus = new Eventbus()

Classic methods

.emit(evt, ...args) - emit event

bus.emit("foo", "bar", "baz")

.on(evt, cb) - add event listener

bus.on("foo", console.log)
// => bar baz (According to previous example)

.once(evt, cb) - add self-destructable event listener

bus.once("foo", console.log)

bus.emit("foo", "bar", "baz")
// => bar baz

bus.emit("foo", "bar", "baz")
// => nothing (event was removed)

.off(evt, cb) - remove event listener

bus.off("foo")

bus.emit("foo", "bar")
// => nothing because listener is removed

More fun

.onMany(events) - add many events

bus.onMany({
  foo: [cb1, cb2],
  bar: [cb3]
})

.offAll() - remove all listeners

bus.offAll()

Extending and inheritance

.sendTo(bus) - send events to another bus

const bus1 = new Eventbus()

const bus2 = new Eventbus()

bus1.on("foo", console.log)

bus1.sendTo(bus2)

bus2.emit("foo", "bar baz")
// => bar baz (bus2 got events from bus1)

.fork() - fork bus

const bus1 = new Eventbus()
bus1.on("aaa", console.log)

const bus2 = bus.fork()

bus2.emit("aaa", "bar")
// => bar (events are inherited from bus1)

bus.on("bbb", console.log)
bus2.emit("bbb", "bar")
// => nothing (because event was send to bus1 after fork)

bus2.on("ccc", console.log)
bus.emit("ccc", "bar")
// => nothing (because event was send to bus2 after fork)

.merge(bus2) - fork current bus with of events of both (bus and bus2) buses

const bus = new Eventbus()
bus.on("aaa", console.log)

const bus2 = new Eventbus()
bus.on("bbb", console.log)

const bus3 = bus.merge(bus2)
bus3.emit("aaa", "bar")
// => bar (event from bus)
bus3.emit("bbb", "bar")
// => bar (event from bus2)

bus3.on("ccc", console.log)
bus.emit("ccc", "bar")
// => nothing (it's a fork)
bus2.emit("ccc", "bar")
// => nothing (it's a fork)

.injectTo(instance) - adds .on, .off, .onMany, .offMany, .offAll and .emit methods of forked bus to some instance

const smth = {}

const bus = new Eventbus()
bus.on("test", console.log)

bus.injectTo(smth)
smth.on("foo", console.log)
smth.emit("foo", "bar")
// => bar

bus.emit("test", "bar")
// => bar (inherited from bus)

bus.on("test", console.log)
smth.emit("test", "bar")
// => nothing (it's a fork)

bus.emit("foo", "bar")
// => nothing (it's a fork)

.injectObserverTo(newInstance) - adds only .on and .off methods

const smth = {}

const bus = new Eventbus()
bus.on("test", console.log)

bus.injectObserverTo(smth)
smth.on("foo", console.log)
smth.emit("foo", "bar")
// => bar

bus.emit("test", "bar")
// => bar (inherited from bus)

bus.on("test", console.log)
smth.emit("test", "bar")
// => nothing (it's a fork)

bus.emit("foo", "bar")
// => nothing (it's a fork)