can't build at create-react-app boilerplate

## version
* awaiting v3.0.0
* create-react-app v1.0.5

`yarn run start` can work fine
`yarn run build` will get a error
```bash
static/js/main.ab319118.js from UglifyJs
Unexpected token operator «*», expected punc «(» [./~/awaiting/dist/awaiting.common.js:80,0][static/js/main.ab319118.js:9708,47]
```