带传播算子的打字稿题词

Question

I'm trying to do pretty trivial: Pass a typed object into a function, augment it with known keys, and return a type that intersects the two.

The following code seems to get me most of the way

interface Success {
  success: boolean
}

interface Named {
  name: string
}

type Resolver<T> = Success & T

function test<T>(input: T): Resolver<T> {
  return {
    success: true,
    ...input
  }
}

const person: Named = { name: 'Bob' };
const res = test<Named>(person);
// `res.success` and `res.name` are inferred

However, I get the following error on the ...input spread operator:

How do I coerce T to be an object? I've tried creating an indexed interface and extending that, but the same error persists.

Answer 1

This is a TypeScript bug. It will be fixed by PR https://github.com/Microsoft/TypeScript/pull/13288