How to avoid redundant types/interfaces

[grosch]

My object is essentially defined like so

export type ISomeThing = {
   foo: string
   bar: ISomeOtherThing[]
}

class SomeThing implements ISomeThing {
  ...
}

And now I want to use that as a strongly typed form. However, I can't, because the form needs bar's type to be FormArray<ControlsOf<ISomeOtherThing>>, so I end up having to create something like:

export type ISomeThingForm = {
  foo: string
  bar: FormArray<ControlsOf<ISomeOtherThing>>
}

Now that means I have to create methods to convert to/from those as well. This feels very heavy-handed, and I hope I'm missing something obvious here so that I don't have to create a bunch of almost duplicate types.

I'm using version 4.0.4 with Angular 13.