text: //app.js
  App({
    onLaunch: function() {
      //调用API从本地缓存中获取数据
      var logs = wx.getStorageSync('logs') || []
      logs.unshift(Date.now())
      wx.setStorageSync('logs', logs)
    },
  
    getUserInfo: function(cb) {
      var that = this
      if (this.globalData.userInfo) {
        typeof cb == "function" && cb(this.globalData.userInfo)
      } else {
        //调用登录接口
        wx.getUserInfo({
          withCredentials: false,
          success: function(res) {
            that.globalData.userInfo = res.userInfo
            typeof cb == "function" && cb(that.globalData.userInfo)
          }
        })
      }
    },
    globalData: {
      userInfo: null
    },
  })
  