A simple event manager JS (browser) with an simple API like socket.io : on and emit function

SimpleEventManager.js

'use strict';

/**
 * SimpleEventManager is a simple API for create and listen Event
 * It's a superset of DOM Event listening API
 * 
 * Example :

    let event = new SimpleEventManager(function(lastState) {
        // watched variable
        let actualNbThings = document.querySelectorAll('.things').length;

        // verify if it changed
        if (lastState.nbThings != actualNbThings) {
            // emit event
            this.emit('nbthings-changed', {
                last: lastState.nbThings,
                actual: actualNbThings
            });

            // actualyze variable
            lastState.nbThings = actualNbThings
        }
    });

    // log data and event on change
    event.on('nbthings-changed', function(data, event) {
        console.log(data);
        console.log(event);
    });

    // create new .things element.
    let div = document.createElement('div');
    div.className = 'things';
    document.body.appendChild(div);

    // or simply
    let event = new SimpleEventManager();

    event.on('take-that-bitch', function(data) {
        console(data.msg);
    })

    event.emit('take-that-bitch', {
        msg: 'goal !'
    })

    // or that, eventLoop management
    let event = new SimpleEventManager();

    // log data and event on change
    event.on('nbthings-changed', function(data, event) {
        console.log(data);
        console.log(event);
    });

    event.start(function(lastState) {
        // watched variable
        let actualNbThings = document.querySelectorAll('.things').length;

        // verify if it changed
        if (lastState.nbThings != actualNbThings) {
            // emit event
            this.emit('nbthings-changed', {
                last: lastState.nbThings,
                actual: actualNbThings
            });

            // actualyze variable
            lastState.nbThings = actualNbThings
        }
    }, 1000)

    document.querySelector('#btn-stop-event').addEventListener('click', function() {
        event.stop();
    });
    document.querySelector('#btn-start-event').addEventListener('click', function() {
        event.start();
    });

 */
class SimpleEventManager {

    /**
     * eventLoop : function(lastState) - binded this : SimpleEvent instance (Optional)
     *  - save eventLoop in instance for futur usage
     * refresh : number in ms (Optional, 60 by default)
     */
    constructor(eventLoop, refresh) {
        this.lastState = {};
        this.start(eventLoop, refresh);
    }

    /**
     * Stop the eventLoop
     */
    stop() {
        clearInterval(this.idRefresh);
    }

    /**
     * Start a new eventLoop with another refresh time
     * - if eventLoop not precise, take the eventLoop of constructor
     *  - if no saved eventLoop, start nothing
     * eventLoop : function(lastState) - binded this : SimpleEvent instance (Optional)
     *  - save eventLoop in instance for futur usage
     * refresh : number in ms (Optional, 60 by default)
     */
    start(eventLoop, refresh) {
        if (typeof eventLoop == 'function') {
            this.eventLoop = eventLoop;
        }
        if (typeof this.eventLoop == 'function') {
            this.idRefresh = setInterval(_ => this.eventLoop.call(this, this.lastState), refresh || 60);
        }
    }

    /**
     * Stop eventLoop, restart with another refresh time
     * - if no eventLoop precised, take the eventLoop of constructor
     *  - if no saved eventLoop, restart nothing
     * refresh : number in ms (Optional, 60 by default)
     * eventLoop : function(lastState) - binded this : SimpleEvent instance (Optional)
     *  - save eventLoop in instance for futur usage
     */
    restart(refresh, eventLoop) {
        this.stop();
        this.start(eventLoop, refresh);
    }

    /**
     * name : string (event type)
     * data : any (some data to transmit to event listener) (Optional)
     */
    emit(name, data) {
        var event = new Event(name);
        event.data = data;

        document.dispatchEvent(event);
    }

    /**
     * name : string (event type you want catch)
     * callback : function(data, event) for make some nasty thing with catched event - binded this : SimpleEvent instance
     */
    on(name, callback) {
        document.addEventListener(name, event => callback.call(this, event.data, event));
    }
}