stack.js

class Stack {
  constructor() {
    this._items = [];
  }

  push(element) {
    if (Array.isArray(element)) {
      this._items.push(...element);
    } else {
       this._items.push(element); 
    }
  }

  pop() {
    return this._items.pop();
  }

  peek() {
    return this._items[this._items.length - 1];
  }

  isEmpty() {
    return this._items.length === 0;
  }

  get size() {
    return this._items.length;
  }

  clear() {
    this._items = [];
  }

  print() {
    console.log(this._items.toString());
  }
}