如何利用 JavaScript 实现一个支持插件体系的应用程序框架？

{
  name: 'example-plugin',
  version: '1.0.0',
  install(app) {
    // 注册功能、监听事件、扩展 API
    app.registerFeature('hello', () => console.log('Hello from plugin!'));
  },
  uninstall(app) {
    // 清理资源、移除监听、撤销扩展
    app.unregisterFeature('hello');
  }
}

class PluginManager {
  constructor(app) {
    this.app = app;
    this.plugins = new Map();
  }

  register(plugin) {
    if (this.plugins.has(plugin.name)) {
      console.warn(`Plugin ${plugin.name} already registered.`);
      return false;
    }
    this.plugins.set(plugin.name, plugin);
    return true;
  }

  install(name) {
    const plugin = this.plugins.get(name);
    if (!plugin) throw new Error(`Plugin ${name} not found.`);

    if (typeof plugin.install === 'function') {
      plugin.install(this.app);
    }
  }

  uninstall(name) {
    const plugin = this.plugins.get(name);
    if (plugin && typeof plugin.uninstall === 'function') {
      plugin.uninstall(this.app);
    }
    this.plugins.delete(name);
  }

  installAll() {
    for (const name of this.plugins.keys()) {
      this.install(name);
    }
  }
}

async loadFromUrl(url) {
  const module = await import(url);
  const plugin = module.default;
  this.register(plugin);
}

class EventBus {
  constructor() {
    this.listeners = {};
  }

  on(event, callback) {
    (this.listeners[event] ||= []).push(callback);
  }

  emit(event, data) {
    (this.listeners[event] || []).forEach(cb => cb(data));
  }
}

install(app) {
  app.eventBus.on('userLogin', user => {
    console.log('Plugin detected login:', user);
  });
}