인프런 커뮤니티 질문&답변

type Awaited<T> =
    T extends null | undefined ? T : // special case for `null | undefined` when not in `--strictNullChecks` mode
        T extends object & { then(onfulfilled: infer F, ...args: infer _): any } ? // `await` only unwraps object types with a callable `then`. Non-object types are not unwrapped
            F extends ((value: infer V, ...args: infer _) => any) ? // if the argument to `then` is callable, extracts the first argument
                Awaited<V> : // recursively unwrap the value
                never : // the argument to `then` was not callable
        T; // non-object or non-thenable

여기서 object & { then }도 브랜딩 기법을 사용한 건가요? duck typing과 브랜딩의 차이점이 궁금합니다.