微信小程序 调用远程接口 给全局数组赋值代码实

Page({
 data: {
  bookList: []
 },
 onLoad: function() {
  wx.request({
   url: 'https://jiashubing./wechat/book',
   header: {
    'content-type': 'application/json'
   },
   suess(res) {
    var obj = JSON.parse(res.data)
    console.log(obj)
    this.setData({
     bookList: obj
    })
   }
  })
 }
})

VM3293:1 thirdScriptError
Cannot read property 'setData' of null;at pages/index/index onLoad function;at api request suess callback function
TypeError: Cannot read property 'setData' of null

Page({
 data: {
  bookList: []
 },
 onLoad: function() {
  let that = this
  wx.request({
   url: 'https://jiashubing./wechat/book',
   header: {
    'content-type': 'application/json'
   },
   suess(res) {
    var obj = JSON.parse(res.data)
    console.log(obj)
    that.setData({
     bookList: obj
    })
   }
  })
 }
})