HarmonyOS class有构造函数constructor，那么有析构函数吗？

class Observer { 
  private eventHub: EventHub; 
  constructor(eventHub: EventHub) { 
    this.eventHub = eventHub; 
  } 
  on(type: string, callback: Function) { 
    this.eventHub.on(type, callback); 
  } 
  off(type: string, callback?: Function) { 
    this.eventHub.off(type, callback); 
  } 
} 
export default new Observer(new EventHub());
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