using in WebWorker

I use this library in angular's webworker, I have an error, because in webworker, window is not accessible :

```
Uncaught ReferenceError: Buffer is not defined
    at eval (converter.js:10)
```

Could you check nodeJS's environment otherwise ?

Maybe with this
```
var isNode=new Function("try {return this===global;}catch(e){return false;}");
```

Thank you