I have a npm module called RiveScript that usually (in Javascript) gets instantiated that way:

```
var RiveScript = require('rivescript');
var rivescript = new RiveScript();

```

I'm trying to write a declaration file for the module, but am stuck at the first step. Here's what I've written so far:

```
declare module "rivescript" {

    interface RivescriptOptions {
        utf8?: boolean;
    }

    class RiveScript {
        constructor(options?: RivescriptOptions);
    }

    export default RiveScript;
}

```

Then I guess in Typescript I would be using the module this way (*default import*):

```
import RiveScript from 'rivescript';
let rivescript = new RiveScript();

```

However, `tsc` generates this, which is not valid as it references a `default()` function:

```
const rivescript_1 = require('rivescript');
let rivescript = new rivescript_1.default();

```

What am I doing wrong?