How to convert type to interface in Typescript

user_132610 0
Viewed 7821

From a typed Object, is it possible to transform it into an interface in TypeScript?

I already read this QA here on StackOverflow, and don't think it fits well with the description I give in this Question.

Quick Example, this scenario where type Product is defined as type from a third-party TypeScript library.

# ProductFragmentOne is used to highligt possibility of composition(unions, etc)
type Product = ProductFragmentOne & { sku: string };

To integrate that product in our own system, it is already possible by extending(union) a type as in the following example:

export type ProductSchema = Product & { 
  name: string;
}

My question is:

  • Is there a way for our ProductSchema to be defined as an interface, instead of using the types approach? Or is that even possible?
# Example of how the code may look
export interface ProductSchema{ 
  name: string;
  // do the magic to add Product properties here
}

Update: The reason for this approach is purely preference of interfaces over types. Also to make existing code keep its style, regardless of third party library adopted.

Thanks.

typescript interface types
1 Answers

To solve this problem, I used an answer found on a completely unrelated question: Is it "Possible to extend types in Typescript?".

In fact, since TypeScript 2.2 -- It is possible for an interface to extend a type.

There is an extensive thread on the difference between interface and type on this StackOverflow thread: TypeScript: Interfaces vs Types

export interface ProductSchema extends Product{ 
  name: string;
}
# Where the Product is a type similar to
type Product = { SKU: string }

The "magic trick" I was looking for was indeed that extends operator(or keyword). There is an additional example on TypeScript playground based on this same approach as well

user_1326100
Related