Publish/Subscribe Implementation

PubSub Implementation

EventEmitter = {
    _events: {},
    publish: function (event, data) {
        if (!this._events[event]) return; // no one is listening to this event
        this._events[event].forEach( callback => callback(data) )
    },
    subscribe: function (event, callback) {
      if (!this._events[event]) this._events[event] = []; // new event
      this._events[event].push(callback);
    }
}

const buyer = { __proto__: EventEmitter }
const seller = { __proto__: EventEmitter }

buyer.subscribe('house:price', price => console.log(`NEW PRICE: ${price.value}`) )

seller.publish('house:price', { value: 100 }) // NEW PRICE: 100
seller.publish('house:price', { value: 200 }) // NEW PRICE: 200
seller.publish('house:price', { value: 50 }) // NEW PRICE: 50