README.md

A biblioteca consiste num mapa de valor e ouvintes.

type Handler = (payload: any) => void;

type Listeners = Map<string, Array<Handler>>;

type Emitters = WeakMap<any, Listeners>;

Qualquer valor JavaScript pode ter ouvintes relacionados a ele.

const createEventEmitter = (name: any) => EventEmitter;

createEventEmitter('Sou um valor qualquer').on('Evento', (payload) => console.log('Handler do "Evento". ' + payload))

createEventEmitter('Sou um valor qualquer').emit('Evento', 'Sou o payload do "Evento".')

// Handler do "Evento". Sou o payload do "Evento".

clean-emitter.js

const emitters = new WeakMap();

const getListeners = (name) => emitters.get(name);

const getHandlers = (name, event) => {
  const listeners = getListeners(name);
  const handlers = listeners && listeners.get(event);
  return handlers;
};

const emitter = (name) => ({
  emit (event, payload) {
    const handlers = getHandlers(name, event) || [];
    handlers.forEach((handler) => handler(payload));
    return this;
  },
  on (event, handler) {
    const listeners = getListeners(name);
    const handlers = [ ...getHandlers(name, event) || [], handler ];
    listeners.set(event, handlers);
    emitters.set(name, listeners);
    return this;
  }
});