Queue with private class fields

Queue.js

class Queue{
	#array = []
    enqueue(val){
      return this.#array.push(val);
    }
    dequeue(){
      return this.#array.shift(); 
    }
    isEmpty(){
      return this.#array.length == 0
    }
    peek(){
      if(this.isEmpty()){
        return undefined;
      }
      return this.#array[0];
    }
}