PubSub.js

class PubSub {
  constructor() {
    this.subscribers = {};
  }

  subscribe(event, fn) {
    if (Array.isArray(this.subscribers[event])) {
      this.subscribers[event] = [...this.subscribers[event], fn];
    } else {
      this.subscribers[event] = [fn];
    }
    return () => {
      this.unsubscribe(event, fn);
    };
  }

  unsubscribe(event, fn) {
    this.subscribers[event] = this.subscribers[event].filter(
      (sub) => sub !== fn
    );
  }

  publish(event, data) {
    if (Array.isArray(this.subscribers[event])) {
      this.subscribers[event].forEach((sub) => {
        sub(data);
      });
    }
    return false;
  }
}

export default new PubSub();