引入LeanCloud的JS后，报错

const AV = require('./utils/leancloud.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.login({
        success: function () {
          wx.getUserInfo({
            success: function (res) {
              that.globalData.userInfo = res.userInfo
              typeof cb == "function" && cb(that.globalData.userInfo)
            }
          })
        }
      })
    }
  },
  globalData:{
    userInfo:null
  }
})
AV.init({ 
 appId: "XXX", 
 appKey: "XXXX",
 });
var user = new AV.user();
user.setUsername( 'Tom' );
user.setPassword( 'cat!@#123' );
user.setEmail( 'tom@leancloud.cn' );
user.signUp().then( function( loginedUser ) {
  console.log( loginedUser );
}, ( function( error ) {
}) );

上面是App.js
Console报错为：

app.js:36 Uncaught TypeError: AV.user is not a constructor