type-challenges-judge

Type Challenges Judge

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MapTypes

提出詳細

type MapTypes<T, R extends {mapFrom: unknown, mapTo: unknown}> = {
  [K in keyof T]:
  T[K] extends R["mapFrom"]
  ? R extends {mapFrom: T[K]}
    ? R["mapTo"]
    : never
  : T[K]
}

提出日時	2023-09-18 08:27:40
問題	MapTypes
ユーザー	sankantsu
ステータス	Accepted

テストケース

import type { Equal, Expect } from '@type-challenges/utils'

type cases = [
  Expect<Equal<MapTypes<{ stringToArray: string }, { mapFrom: string; mapTo: [] }>, { stringToArray: [] }>>,
  Expect<Equal<MapTypes<{ stringToNumber: string }, { mapFrom: string; mapTo: number }>, { stringToNumber: number }>>,
  Expect<Equal<MapTypes<{ stringToNumber: string; skipParsingMe: boolean }, { mapFrom: string; mapTo: number }>, { stringToNumber: number; skipParsingMe: boolean }>>,
  Expect<Equal<MapTypes<{ date: string }, { mapFrom: string; mapTo: Date } | { mapFrom: string; mapTo: null }>, { date: null | Date }>>,
  Expect<Equal<MapTypes<{ date: string }, { mapFrom: string; mapTo: Date | null }>, { date: null | Date }>>,
  Expect<Equal<MapTypes<{ fields: Record<string, boolean> }, { mapFrom: Record<string, boolean>; mapTo: string[] }>, { fields: string[] }>>,
  Expect<Equal<MapTypes<{ name: string }, { mapFrom: boolean; mapTo: never }>, { name: string }>>,
  Expect<Equal<MapTypes<{ name: string; date: Date }, { mapFrom: string; mapTo: boolean } | { mapFrom: Date; mapTo: string }>, { name: boolean; date: string }>>,
]