Uglify error on build
When building there is the following error:

```
ERROR in client.264ba4e2.js from UglifyJs
Unexpected token punc «}», expected punc «:» [./src/index.js:20,15][client.264ba4e2.js:7142,66]
```

To reproduce just clone this project: https://github.com/jazoom/ream-minimal
then run:
$ yarn
$ npm run build