微信小程序如何监听全局变量

globalData: {
    red_heart:0,
  },

this.globalData = new Proxy(this.globalData, {
      get(target, key){
        return target[key];
      },
      set:(target, key, value)=>{
        if(key === "red_heart"){
          this.globalDep.RedHeartDep.notifuy()
        }
        return Reflect.set(target, key, value);
      }
    });

globalDep:{
    RedHeartDep:{
      subs:[],
      addSub(watch){
        this.subs.push(watch)
      },
      removeWatch(id){
        this.subs = this.subs.filter((item)=>{
          return item.id != id
        })
      },
      notifuy(){
        setTimeout(()=>{
          this.subs.forEach(w=>w.update())
        },0)
      }
    }
  }

const app = getApp()
Component({
  properties: {

  },
  data: {
    red_heart:0
  },
  lifetimes:{
    attached(){
      let watch = {
        id:this.__wxExparsernodeId__,
        update:()=>{
          this.setData({
            red_heart:app.globalData.red_heart
          })
        }
      }
      app.globalDep.RedHeartDep.addSub(watch)
      app.globalData.red_heart = app.globalData.red_heart
    },
    detached(){
      app.globalDep.RedHeartDep.removeWatch(this.__wxExparserNodeId__)
    }
  },
  methods: {
    handClick(){
      app.globalData.red_heart++
      console.log(app.globalData)
    }
  }
})