Generic interface with generic type parameter as another generic interface without declared parameter

[archfz]

Search Terms

generic parameter for interface as another generic interface
generic interface parameter nesting
generic interface with proxied generic parameter

Suggestion

I would like to be able to define a generic interface T where X would be another generic interface and to be able to restrict how many generic parameters it would provide. Maybe best I could write it as interface T<X<any>> to require 1 generic type with 1 generic parameter, but that parameter would have to be added not in the declaration of the interface but in the declarations inside the body of the interface.

Use Cases

An example use case would be of having a provider that serves some types A, B, C wrapped in another object that can have a generic type ParameterBag.

interface Provider<ParameterBag<any>> {
  getA(): ParameterBag<A>
  getB(): ParameterBag<B>
  getC(): ParameterBag<C>
} 

interface ParmeterBagKind<T> { }
class ProviderKind implements Provider<ParmeterBagKind> { }

Checklist

My suggestion meets these guidelines:

• [ x ] This wouldn't be a breaking change in existing TypeScript/JavaScript code
• [ x ] This wouldn't change the runtime behavior of existing JavaScript code
• [ x ] This could be implemented without emitting different JS based on the types of the expressions
• [ x ] This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, etc.)
• [ x ] This feature would agree with the rest of TypeScript's Design Goals.

[jcalz]

Duplicate of #1213

[archfz]

Is there a typescript vocabulary that gives all of these words for the generic typing specifics? Searching for existing issue for this was hard for me because I was not able to construct with proper names what I would like.

[archfz]

Also I will close this as of duplicate.

[jcalz]

Is there a typescript vocabulary that gives all of these words for the generic typing specifics? Searching for existing issue for this was hard for me because I was not able to construct with proper names what I would like.

Not that I know of; the only reason I knew this was a duplicate is because I remembered the existing issue. In other languages this is usually called "higher kinded types" but I don't know if there's a single canonical terminology for this or anything else in TypeScript.