Mediator pattern es3 to es6

mediator-pattern.js

// es3: https://gist.github.com/addyosmani/1837327
var mediator = (function() {
    // Subscribe to an event, supply a callback to be executed 
    // when that event is broadcast
    var subscribe = function(channel, fn) {
            if (!mediator.channels[channel]) mediator.channels[channel] = [];
            mediator.channels[channel].push({
                context: this,
                callback: fn
            });
            return this;
        },

        // Publish/broadcast an event to the rest of the application
        publish = function(channel) {
            if (!mediator.channels[channel]) return false;
            var args = Array.prototype.slice.call(arguments, 1);
            for (var i = 0, l = mediator.channels[channel].length; i < l; i++) {
                var subscription = mediator.channels[channel][i];
                subscription.callback.apply(subscription.context, args);
            }
            return this;
        };

    return {
        channels: {},
        publish: publish,
        subscribe: subscribe,
        installTo: function(obj) {
            obj.subscribe = subscribe;
            obj.publish = publish;
        }
    };

}());

//es6
const mediator = ((() => {

    /**
     * @description Subscribe to an event, supply a callback to be executed when that event is broadcast
     * @param store {string}
     * @param fn {function}
     * @returns {subscribe} {object}
     */
    const subscribe = function(store, fn) {

        if (!mediator.stores[store]) {
            mediator.stores[store] = [];
        }

        mediator.stores[store].push({
            context: this,
            callback: fn
        });

        return this;
    };

    /**
     * @description Publish/broadcast an event to the rest of the application
     * @param store {string}
     * @param args {object}
     * @returns {*||boolean}
     */
    const publish = function(store, ...args) {

        if (!mediator.stores[store]) {
            return false;
        }

        for (let value of mediator.stores[store]) {
            const subscription = value;
            subscription.callback.apply(subscription.context, args);
        }

        return this;
    };

    return {
        stores: {},
        publish,
        subscribe,
        installTo(obj) {
            obj.subscribe = subscribe;
            obj.publish = publish;
        }
    };
})());