import Emitter from './Emitter';

const emitter = new Emitter();

emitter.on('connect', data => {
  console.log('We have been connected to', data);
});

emitter.on('disconnect', data => {
  console.log('We disconnected from', data);
});

emitter.emit('connect', 'http-server');
// prints to console:
// > We have been connected to http-server
emitter.emit('connect', 'websocket');
// prints to console:
// > We have been connected to websocket

emitter.emit('disconnect', 'websocket');
// prints to console:
// > We disconnected from websocket
emitter.emit('disconnect', 'http-server');
// prints to console:
// > We disconnected from http-server

class Emitter {
constructor() {
    this.events = {};
}
on(eventName, fn) {
    if (!this.events[eventName]) {
        this.events[eventName] = [];
    }

    this.events[eventName].push(fn);
}
emit(eventName, data) {
    const event = this.events[eventName];
    if (event) {
        event.forEach(fn => {
            fn.call(null, data);
        });
    }
    return () => {
        this.events[eventName] =

this.events[eventName].filter(eventFn => fn !== eventFn);
        }
    }
}
let emitter = new Emitter();

emitter.on('connect', data => {
    console.log('We have been connected to', data);
});

emitter.on('disconnect', data => {
    console.log('We disconnected from', data);
});

emitter.emit('connect', 'http-server');
// prints to console:
// > We have been connected to http-server
emitter.emit('connect', 'websocket');
// prints to console:
// > We have been connected to websocket

emitter.emit('disconnect', 'websocket');
// prints to console:
// > We disconnected from websocket
emitter.emit('disconnect', 'http-server');
// prints to console:
// > We disconnected from http-server