如何通过链表添加最大长度为20的堆栈

class Node {
  constructor(value) {
    this.value = value;
    this.next = null;
  }
}

class Stack {
  constructor() {
    this.top = null;
    this.length = 0;
  }

  push(value) {
    if (this.length < 20) {
      const newNode = new Node(value);
      newNode.next = this.top;
      this.top = newNode;
      this.length++;
    } else {
      console.log("堆栈已满，无法添加新元素。");
    }
  }

  pop() {
    if (this.length > 0) {
      const value = this.top.value;
      this.top = this.top.next;
      this.length--;
      return value;
    } else {
      console.log("堆栈为空，无法移除元素。");
    }
  }

  peek() {
    if (this.length > 0) {
      return this.top.value;
    } else {
      console.log("堆栈为空，无法获取顶部元素。");
    }
  }

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

  isFull() {
    return this.length === 20;
  }
}

// 示例用法
const stack = new Stack();
stack.push(1);
stack.push(2);
stack.push(3);
console.log(stack.pop()); // 输出：3
console.log(stack.peek()); // 输出：2
console.log(stack.isEmpty()); // 输出：false
console.log(stack.isFull()); // 输出：false