小程序加载云端数据库中的第二页数据，前端如何动态显示？

export default class HelloLoading{

  constructor(collection_name,db){
    this.collection_name = collection_name

    this.db = db
    this.setPageCount(db)
  }

  pageCount = 0;

  setPageCount(db){

    db.collection(this.collection_name).count({
      success:function(res){
        // console.log(res.total)
        this.pageCount = res.total
      },
      fail: console.error
    })

  }

  getPageCount(){
    return this.pageCount
  }


}

export default class HelloLoading{

  static pageCount = 0;

  constructor(collection_name){
    this.collection_name = collection_name

    this.db = wx.cloud.database()
   
  }

  setPageCount(callback){

    this.db.collection(this.collection_name).count({
      success:function(res){
        
        console.log(res.total)
        HelloLoading.pageCount = res.total

        callback()
      },
      fail: console.error
    })

  }

  getPageCount(){
    return HelloLoading.pageCount;
  }

}

loadingdata.setPageCount(function(){
      console.log(loadingdata.getPageCount())
    })