JS如何实现组合模式？组合的结构

// 抽象组件
class Component {
  constructor(name) {
    this.name = name;
  }

  add(component) {
    throw new Error("Cannot add to a leaf node."); // 默认叶子节点不支持添加
  }

  remove(component) {
    throw new Error("Cannot remove from a leaf node."); // 默认叶子节点不支持移除
  }

  getChild(index) {
    throw new Error("Cannot get child from a leaf node."); // 默认叶子节点不支持获取子节点
  }

  operation() {
    throw new Error("Operation must be implemented by subclasses.");
  }
}

// 叶子节点
class Leaf extends Component {
  constructor(name) {
    super(name);
  }

  operation() {
    return `Leaf: ${this.name}`;
  }
}

// 组合节点
class Composite extends Component {
  constructor(name) {
    super(name);
    this.children = [];
  }

  add(component) {
    this.children.push(component);
  }

  remove(component) {
    const index = this.children.indexOf(component);
    if (index > -1) {
      this.children.splice(index, 1);
    }
  }

  getChild(index) {
    return this.children[index];
  }

  operation() {
    let result = `Composite: ${this.name}\n`;
    for (const child of this.children) {
      result += "  " + child.operation() + "\n";
    }
    return result;
  }
}

// 使用示例
const root = new Composite("Root");
const branch1 = new Composite("Branch1");
const branch2 = new Composite("Branch2");

const leaf1 = new Leaf("Leaf1");
const leaf2 = new Leaf("Leaf2");
const leaf3 = new Leaf("Leaf3");

branch1.add(leaf1);
branch1.add(leaf2);

branch2.add(leaf3);

root.add(branch1);
root.add(branch2);

console.log(root.operation());