[bug report] what's wrong with this startup service?

### Element UI version
2.13.0

### OS/Browsers version
win10/chrome

### Vue version
2.5.17

### Reproduction Link
https://codepen.io/lwm98/pen/yLVGJQO

### Steps to reproduce
1.cnpm install 启动服务
2.报错
ERROR Failed to compile with 1 error
error in ./node_modules/_element-ui@2.13.0@element-ui/packages/scrollbar/src/main.js

Module parse failed: Unexpected token (65:6)
You may need an appropriate loader to handle this file type, currently no loaders are configured to process this file. See https://webpack.js.org/concepts#loaders
| }, this.$slots.default);
| const wrap = (
>