Hello! @immutable-js/maintainers @Methuselah96

We currently use Immutable.js pretty extensively in a Redux store and are progressively moving to TypeScript. In trying to strongly type our Immutable.Map objects, I settled for the time being on this:

export type FontUpload = Immutable.Map<
  'name' | 'created' | 'errorMessage' | 'progress' | 'complete',
  never
>;

It's less than ideal for strongly typing our stores, and given the option something like this would be great:

export type FontUpload = Immutable.Map<{
  name: string,
  created: number,
  errorMessage?: string,
  progress?: number,
  complete?: boolean
}>;

Is this something Immutable.js would be interested in for the v4.0.0 release? Happy to help with this work as long as devs find it reasonable.

I may need some TS help with overloading generics, if that's even possible. Would anyone know about the feasibility of this?

Best,