My Observe Pattern implementation using classes

ObservePattern.js

class Observer {
  #id
  #container
  
  constructor() {
    this.#id = 0
    this.#container = {}
  }

  subscribe(topic, f) {
    if (!(topic in this.#container)) {
      this.#container[topic] = [];
    }
    this.#container[topic].push({
      'id': ++this.#id,
      'callback': f
    });
    return this.#id;
  }
 
  unsubscribe(topic, id) {
    let subscribers = [];
    for (const subscriber of this.#container[topic]) {
      if (subscriber.id !== this.#id) {
        subscribers.push(subscriber);
      }
    }
    this.#container[topic] = subscribers;
  }
         
  publish(topic, data) {
    for (const subscriber of this.#container[topic]) {
      subscriber.callback(data);
    }
  }
}

usageEmaple.js

const observe = new Observer()

let subscriptionID1 = observe.subscribe('mouseClicked', (data) => {
  console.log('mouseClicked', JSON.stringify(data))
})

let subscriptionID2 = observe.subscribe('mouseHovered', (data) => {
  console.log('mouseHovered', JSON.stringify(data))
})


// When we publish an event, all callbacks should
// be called and you will see three logs
observe.publish('mouseClicked', {
  "data": "data1"
})

observe.publish('mouseHovered', {
  "data": "data2"
})

// We unsubscribe an event
observe.unsubscribe("mouseClicked", subscriptionID1)

// now we have 1 log
observe.publish('mouseClicked', {
  "data": "data1"
})

observe.publish('mouseHovered', {
  "data": "data2"
})