2 - Get Return Type
- #TypeScript
- #Type Challenges
질문
내장 제네릭 ReturnType<T>을 이를 사용하지 않고 구현하세요.
예시:
const fn = (v: boolean) => {
if (v)
return 1
else
return 2
}
type a = MyReturnType<typeof fn> // should be "1 | 2"
// !collapse(1:30) collapsed
/* _____________ 테스트 케이스 _____________ */
import type { Equal, Expect } from '@type-challenges/utils'
type cases = [
Expect<Equal<string, MyReturnType<() => string>>>,
Expect<Equal<123, MyReturnType<() => 123>>>,
Expect<Equal<ComplexObject, MyReturnType<() => ComplexObject>>>,
Expect<Equal<Promise<boolean>, MyReturnType<() => Promise<boolean>>>>,
Expect<Equal<() => 'foo', MyReturnType<() => () => 'foo'>>>,
Expect<Equal<1 | 2, MyReturnType<typeof fn>>>,
Expect<Equal<1 | 2, MyReturnType<typeof fn1>>>,
]
type ComplexObject = {
a: [12, 'foo']
bar: 'hello'
prev(): number
}
const fn = (v: boolean) => v ? 1 : 2
const fn1 = (v: boolean, w: any) => v ? 1 : 2