interface - Does Typescript support "subset types"?

Question

Let's say I have an interface:

interface IUser {
  email: string;
  id: number;
  phone: string;
};

Then I have a function that expects a subset (or complete match) of that type. Maybe it will pass an entire object, made it will just pass in {email: "[email protected]"}. I want the type checker to allow for both.

Example:

function updateUser(user: IUser) {
  // Update a "subset" of user attributes:
  $http.put("/users/update", user);
}

Does Typescript support this sort of behavior yet? I could find it very useful, particularly with paradigms like Redux.

To clarify, the goal is:

1. Avoid re-writing an interface and manually setting all attributes to optional.
2. Avoid assignment of unexpected attributes (such as spelling mistakes).
3. Avoid imperative logic such as if statements, which forfeit benefits of compile time type checking.

UPDATE: Typescript has announced support for mapped types which should solve this problem once published.

question from:https://stackoverflow.com/questions/36871057/does-typescript-support-subset-types

Answer 1

Typescript now supports partial types.

The correct way to create a partial type is:

type PartialUser = Partial<IUser>;