## Uncaught Error: Module must be loaded as AMD or CommonJS
at ng2-bootstrap.umd.min.js:5680
at ng2-bootstrap.umd.min.js:1
at ng2-bootstrap.umd.min.js:5674
(SystemJS) exports is not defined
ReferenceError: exports is not defined
at eval (http://localhost:5555/app/shared/models/question.model.js:2:23)
at eval (<anonymous>)
at Object.eval (http://localhost:5555/app/shared/models/index.js:6:10)
at eval (http://localhost:5555/app/shared/models/index.js:11:4)
Evaluating http://localhost:5555/app/shared/models/question.model.js
Evaluating http://localhost:5555/app/shared/models/index.js
Evaluating http://localhost:5555/app/shared/index.js
Evaluating http://localhost:5555/app/app.component.js
Evaluating http://localhost:5555/app/app.module.js
Evaluating http://localhost:5555/app/main.js
Error loading http://localhost:5555/app/main.js Not expecting this error? Report it at https://github.com/mgechev/angular-seed/issues
## Uncaught Error: Module must be loaded as AMD or CommonJS at ng2-bootstrap.umd.min.js:5680 at ng2-bootstrap.umd.min.js:1 at ng2-bootstrap.umd.min.js:5674
(SystemJS) exports is not defined
请教一下这是什么原因导致的,该怎么解决啊