Handling declaration files?

I had to monkeypatch the code to include declaration files:

```
var declarationFiles = _b.compilerConfig.fileNames.filter(f => f.endsWith(".d.ts"));
var files = [sourceFileName].concat(declarationFiles);
var program = typescript_1.default.createProgram(files, options, compilerHost);
```

Am I missing something or doing something wrong?