const PubSub = {

    callbacks: {},

    subscribe(ch, callback) {
        const calls = this.callbacks;
        callback = callback || this.render;
        (calls[ch] || (calls[ch] = [])).push(callback);

        return () => {
            delete calls[ch];
            return calls;
        }
    },

    publish() { //dispatch
        let args = [].slice.call(arguments, 0);
        let ch = args.shift();

        if (!this.callbacks || !this.callbacks[ch]) {
            throw new Error(ch + ' not exist');
            return this;
        }

        // dispatch to update redux store. cb==render
        this.callbacks[ch].forEach(cb => cb(args));

        return this;
    },

    render () {
        console.log('PubSub default callback')
    }
}

PubSub.subscribe('channel1', () => console.log('callback 1'));
PubSub.subscribe('channel2', (val) => console.log('callback 2: ' + val));
PubSub.subscribe('channel3', (ary) => console.log('callback 3', ary));

PubSub.publish('channel1');  //callback 1
PubSub.publish('channel2', 123);  //callback 2: 123
PubSub.publish('channel3', [1, 2, 3]); //callback 3 [1, 2, 3]

const unsubscribe = PubSub.subscribe('channel6');
unsubscribe();

PubSub.publish('channel4', [1, 2, 3]); //callback 3 [1, 2, 3]

function ManageStore(reducer) {
    this.state = null;
    this.listeners = [];
    this.reducer = reducer || this.reducerAction;

    //TODO: settings;
    console.log(ManageStore == this, ManageStore === this);

    this.dispatch({});
}

ManageStore.prototype = {

    getState () {
        return this.state;
    },

    dispatch (action) {
        this.state = this.reducer(this.state, action);
        this.listeners.forEach(listener => listener())
    },

    subscribe(listener) {
        this.listeners.push(listener);
        return () => {
            this.listeners = this.listeners.filter(l => l !== listener)
        }
    },

    reducerAction (state, action) {
        return this.state;
    }
};

ManageStore.prototype.constructor = ManageStore;

ManageStore.state = {};

let store = new ManageStore();
store.state === ManageStore.state; //false

//https://github.com/cowboy/jquery-tiny-pubsub/blob/master/src/tiny-pubsub.js
(function ($) {

    const o = $({});

    $.subscribe = () => o.on.apply(o, arguments);

    $.unsubscribe = () => o.off.apply(o, arguments);

    $.publish = () => o.trigger.apply(o, arguments);

}(jQuery));