微信小程序 上拉加载分页

js：

Page({
  data: {
    data: [],
    page: 1,
    last_page: 0
  },
  onLoad() {
    let page = this.data.page
    this.list(page)
  },
  list(page) {
    wx.request({
      url: 'http://www.xxx.com?page=' + page,
      success: res => {
        let newData = res.data.data.data
        let oldData = this.data.data
        let data = oldData.concat(newData)
        this.setData({
          data: data,
          last_page: res.data.data.last_page,
          page
        })
      }
    })
  },
  onReachBottom: function () {
    let page = this.data.page + 1
    let last_page = this.data.last_page
    if(page > last_page){
      this.setData({
        page:last_page
      })
    }else{
      this.list(page)
    }
  },
})

后端php（laravel框架）：

public function index()
    {
        $data = VocalConcert::orderBy('attendance','desc')->paginate(4);
        $items = $data->items();
        $last_page = $data->lastPage();
        return ['code'=>10001,'msg'=>'请求成功','data'=>['data'=>$items,'last_page'=>$last_page]];
    }