In a Stack data structure, the last element added is the first one to be removed (LIFO). The peek method should return the last element added, not the first one.

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

  push(element) {
    this.items.push(element);
  }

  pop() {
    if (this.isEmpty()) {
      throw new Error("Stack is empty");
    }
    return this.items.pop();
  }

  peek() {
    if (this.isEmpty()) {
      throw new Error("Stack is empty");
    }
    return this.items[this.items.length - 1];
  }

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

  size() {
    return this.items.length;
  }

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