Typescript Helper Functions not working

Hi 

We use typescript and I was testing a component that works perfectly in Storybook exposing the types but in Uxpin doesn't return any times.

The types used was 

```
export type FooType = Omit<BarType, 'type'> & {
 type: boolean
}
```

Weirdly if I wrote it as 
```
export interface FooType extends Omit<BarType, 'type'> {
 type: boolean
}
```

it works

