Type Inference in Conditional Types

Background

The infer keyword enables powerful type extraction patterns, forming the basis of ReturnType and Awaited types.

Problem

Create conditional types that extract the return type of a function and the resolved type of a Promise using infer.

Input

A function or Promise type to extract from.

Output

The extracted inner type (return type or Promise resolved type).

Sample tests

Input: () => string

Expected: string (return type)

Your solution

Learning objective

Master the infer keyword for type extraction in conditional types.