This is not the correct translation. It should be:

 ```javascript
var reverse;

if ((reverse = attr.charAt(0) === '-')) {
...
```

Which stores boolean indicating if first character is `-`. What you have here stores the first character in reverse which means that it will always be reverse in [this line](https://github.com/cbmi/cilantro/pull/594/files#diff-35ae330b63cb501ab72b6a3cd7ceac2fR52).