16:02:52.765 应用【demo】已启动
16:02:53.563report]SException >>>>exception function:createInstanceContext,exception:white screen causecreateinstanceContextfailed,checkjs
stack->Uncaught TypeError:Cannot read property yuserAgent’ofundefined
atisIOS(app-service.js:5962:69)
at (app-service.js:5930:31)
at webpack_require (app-service.js:80:30)
at (app-service.js:5337:20)
Webpack_require at (app-service.js:80:30)
at (app-service.js:3447:37)
webpack_require at (app-service.js:80:30)
at (app-service.js:1217:43)
webpack_require at (app-service.js:80:30)
at eval(<anonymous>:8:36)
uniapp引入vant-ui,在真机运行上会报错咋办急