CODEWITHSUNDEEP
typescript
user578895
user578895

Reputation:

declaring a typescript type within a class

I have a class that has some pretty complicated types based on the generics passed to the class. I use these same types in a few places and I'm trying to figure out how to make them reusable:

class Foo<T> {
  method(): SomeComplicateType<T> {}
  method2(): SomeComplicateType<T> {}
}

The only thing I can come up with is this, but it allows the user to overwrite the type which I don't want:

class Foo<T, U=SomeComplicatedType<T>> {
  method(): U {}
  method2(): U {}
}

Upvotes: 1

Views: 82

Answers (2)

Paleo
Paleo

Reputation: 23772

Sorry for this obvious suggestion but you could use an alias:

type NiceName<T> = SomeComplicateType<T>

class Foo<T> {
  method(): NiceName<T> {}
  method2(): NiceName<T> {}
}

Upvotes: 0

basarat
basarat

Reputation: 276343

TypeScript doesn't allow type creation between the two scopes: 

class A<Scope1> {
  x():Scope2;
}

Your solution

What you have found is a way to create it as a chain in Scope1.

Thoughts

Personally I would bite the bullet and not try to create a new type. I prefer explicit work whenever possible.

Upvotes: 1

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