Implement task #74 - event emmiter

[brian-ai-assistant[bot]]

Event Emitter Class

Here is the implementation of the event emitter class:

class EventEmitter {
  constructor() {
    this.events = {};
  }

  subscribe(eventName, listener) {
    if (!this.events[eventName]) {
      this.events[eventName] = [];
    }

    this.events[eventName].push(listener);
  }

  unsubscribe(eventName, listener) {
    if (this.events[eventName]) {
      this.events[eventName] = this.events[eventName].filter((l) => l !== listener);
    }
  }

  emit(eventName, ...args) {
    if (this.events[eventName]) {
      this.events[eventName].forEach((listener) => listener(...args));
    }
  }
}

Explanation:

• The EventEmitter class is constructed with an empty events object to store the event listeners.
• The subscribe method takes an eventName and a listener function. It adds the listener to the corresponding event's array in the events object. If the event doesn't exist, it creates a new array.
• The unsubscribe method removes the listener from the array of the given eventName if it exists.
• The emit method triggers all the listeners of the given eventName by calling them with any additional arguments passed.

Commit Message: Implement event emitter class