A very simple event emitter with a better API than all the others.

It's better because:

1. on and once return an unsubscribe function
2. It doesn't use this, which means you can pass around the on or emit functions
3. It can take in any existing object and turn it into an emitter

Also, it's pretty simple. Check out the source code.

npm i better-emitter

const createEmitter = require('better-emitter')

API

const emitter = createEmitter()

const unsubscribe = emitter.on('thing happened', (really, { stopPropagation }) => {
	really // => true
	typeof stopPropagation // => 'function'
})

emitter.emit('thing happened', true)

unsubscribe()

emitter = createEmitter([obj])

This is the function exported by the module. It creates a new event emitter object. You can also pass in any object you want, and event emitter functions will be added to it.

unsubscribe = emitter.on(eventString, listenerFunction)

Adds an event listener function. Returns an unsubscribe function that, when called, prevents the listener from firing any more.

The listener function will be passed the optional argument that you passed into emit, as well as an object with a stopPropagation function that you can call to prevent any other listeners from getting the message.

unsubscribe = emitter.once(eventString, listenerFunction)

Just like the on function, except the listener is automatically unsubscribed after the first time the event is emitted.

emitter.emit(eventString, [arg])

Calls all listeners of the given event string, with one optional argument.

emitter.removeAllListeners()

Unsubscribes all current event listeners.

License

WTFPL