执行npm start后这个页面，出不来图片
控制台报错
[HMR] Waiting for update signal from WDS...
localhost/:21 Uncaught TypeError: Super expression must either be null or a function, not undefined
(program):37 [WDS] Hot Module Replacement enabled.
(program):37 [WDS] Warnings while compiling.
看不懂是什么意思，求指教
