messageBus

var messageBus = {

    subscrib: function(str, callback) {
        // make a key in the parent object 
        if (!this[str]) {
            this[str] = [];
            this[str].push(callback)
        } else {
            this[str].push(callback)
        }
    },
    publish: function(str, val) {
        console.log(str)
        for ( property in this) {
            console.log(property)
        }

        if(str!=='topic') {
            return 'no subscriber for that topic';
        }
        for(let i = 0; i < this[str].length; i++) {
            this[str][i](val);
        }
    }
}


messageBus.subscrib('topic', (arr)=> {
    console.log('callback called!', arr)
});
messageBus.subscrib('topic', (arr)=> {
    console.log('callback2 called!', arr)
});
messageBus.publish('topic', 2)