Type Challenges: 00898-easy-includes Solution

// your answers
type Includes<T extends readonly any[], U> = T extends [infer F, ...infer Last] ? Equal<F, U> extends true ? true : Includes<Last, U> : false

Solution by AlexBraunMagic #36913

type Includes<T extends readonly any[], U> = {[P in T[number]]: true}[U] extends true ? true : false;

Solution by shaishabcoding #36847

type Includes<T extends readonly unknown[], I> = I extends T[number]
  ? true
  : false;

Solution by atul60 #36830

type Includes<T extends any[], U> = boolean extends {
  [key in keyof T]: Equal<T[key], U> extends true ? true : false ;
};

Solution by Abdullah-Elsayed01 #36806

解题思路: 重新映射数组中每一项索引的值，判断数组中是否存在 true

// 你的答案
type AnyTrue<T extends readonly boolean[]> =
  true extends T[number] ? true : false;


type Includes<T extends readonly any[], U> = AnyTrue<{
  [K in keyof T]: Equal<T[K], U>
}>

Solution by mietl #36804

type Equal1<X, Y> = (<T>() => T extends X ? 1 : 2) extends <T>() => T extends Y
  ? 1
  : 2
  ? true
  : false;

type Includes<T extends readonly any[], U> = T extends [
  infer First,
  ...infer Rest
]
  ? Equal1<First, U> extends true
    ? true
    : Includes<Rest, U>
  : false;

/* _____________ Test Cases _____________ */
import type { Equal, Expect } from '@type-challenges/utils'

type cases = [
  Expect<Equal<Includes<['Kars', 'Esidisi', 'Wamuu', 'Santana'], 'Kars'>, true>>,
  Expect<Equal<Includes<['Kars', 'Esidisi', 'Wamuu', 'Santana'], 'Dio'>, false>>,
  Expect<Equal<Includes<[1, 2, 3, 5, 6, 7], 7>, true>>,
  Expect<Equal<Includes<[1, 2, 3, 5, 6, 7], 4>, false>>,
  Expect<Equal<Includes<[1, 2, 3], 2>, true>>,
  Expect<Equal<Includes<[1, 2, 3], 1>, true>>,
  Expect<Equal<Includes<[{}], { a: 'A' }>, false>>,
  Expect<Equal<Includes<[boolean, 2, 3, 5, 6, 7], false>, false>>,
  Expect<Equal<Includes<[true, 2, 3, 5, 6, 7], boolean>, false>>,
  Expect<Equal<Includes<[false, 2, 3, 5, 6, 7], false>, true>>,
  Expect<Equal<Includes<[{ a: 'A' }], { readonly a: 'A' }>, false>>,
  Expect<Equal<Includes<[{ readonly a: 'A' }], { a: 'A' }>, false>>,
  Expect<Equal<Includes<[1], 1 | 2>, false>>,
  Expect<Equal<Includes<[1 | 2], 1>, false>>,
  Expect<Equal<Includes<[null], undefined>, false>>,
  Expect<Equal<Includes<[undefined], null>, false>>,
]

Solution by AnastasiaSv #36767

// your answers

type Includes<T extends readonly any[], U> = T extends [infer FirstValue,...infer RestValue] ? Equal<U,FirstValue> extends true ? true : Includes<RestValue,U> : Equal<U,T>

Solution by SubramaniyanTN #36674

type Equal<X, Y> =
  (<T>() => T extends X ? 1 : 2) extends <T>() => T extends Y ? 1 : 2
    ? true
    : false

type Includes<T extends readonly any[], U> =
  Equal<T[0], U> extends true
    ? true
    : T extends [infer first, ...infer rest]
      ? rest extends []
        ? false 
        : Includes<rest, U>
      : false;

Solution by dheerajstvpm #36669

// 여기 풀이를 입력하세요
type Includes<T extends readonly any[], U> = T extends [infer Item, ...infer Rest] 
  ? Equal<U, Item> extends true 
    ? true
    : Includes<Rest, U> 
  : false

Solution by seungdeok #36668

type IsEqual<T, U> =
	(<G>() => G extends T ? 1 : 2) extends
	(<G>() => G extends U ? 1 : 2)
		? true
		: false;

type Includes<Value extends any[], Item> =
 Value['length'] extends 1 
  ? IsEqual<Value[0], Item> extends true 
    ? true 
    : false 
  : IsEqual<Value[0], Item> extends true
		? true
		: Value extends [Value[0], ...infer rest]
			 ? Includes<rest, Item>
			 : false

Solution by wiJeeXu #36651

type Equal<X, Y> = (() => T extends X ? 1 : 2) extends (() => T extends Y ? 1 : 2) ? true : false

type Includes<T extends readonly any[], U> = T extends [infer First, ...infer Rest] ? Equal<First, U> extends true ? true : Includes<Rest, U> : false

Solution by ChemieAi #36555

// your answers
type Includes<T extends readonly any[], U> = 
T extends [infer A,...infer B] ? (Equal<U,A> extends true ? true : Includes<B, U>) : false

Solution by duanlvxin #36497

Just for posterity. Solves all.

type Includes<T extends readonly unknown[], U> = [] extends T
  ? false
  : IsEqual<T[0], U> extends true
  ? true
  : T extends [T[0], ...infer Rest]
  ? Includes<Rest, U>
  : false;
type IsEqual<T, U> = (<G>() => G extends T ? 1 : 2) extends <G>() => G extends U
  ? 1
  : 2
  ? true
  : false;

Solution by JMPSequeira #36491

// 你的答案

type Equal<X, Y> = (<T>() => T extends X ? 1 : 2) extends (<
  T
>() => T extends Y ? 1 : 2)
  ? true
  : false;

type Includes<T extends readonly any[], U> = T extends readonly [
  infer First,
  ...infer Rest
]
  ? Equal<First, U> extends true
    ? true
    : Includes<Rest, U>
  : false;

Solution by uuimorty #36465

// your answers
type Includes<T extends readonly any[], U> = T extends [infer First, ...infer Rest]
? Equal<First, U> extends true
  ? true
  : Includes<Rest, U> 
: false;

Solution by ATravelerGo #36434

type Includes<T extends readonly any[], U> = T extends [infer First, ...infer Rest]
  ? Equal<First, U> extends true
    ? true
    : Includes<Rest, U>
  : false;

Solution by alirezaprime #36416

// your answers
type AreEqual<A,B> = (<T>() => T extends A ? 1 : 2) extends (<T>() => T extends B ? 1 : 2) ? true : false;
type Includes<T extends readonly any[], U> = 
T extends []
?
false
: 
T extends readonly [infer S, ...infer R]
?
AreEqual<S,U> extends true
?
true
:
Includes<R,U>
:
false
;

Solution by justBadProgrammer #36390

// 처음에 쓴 코드 
// 밑 경우엔 A|B extends A true  -> 서브타입임으로 참으로 판단되기 떄문 
//  type IsEqual<T,U> = T extends U ? U extends T ? true : false : false



type IsEqual<X, Y> = 
  (<T>() => T extends X ? 1 : 2) extends
  (<T>() => T extends Y ? 1 : 2) 
    ? true 
    : false;

type Includes<T extends readonly any[], U> = T extends [infer First, ...infer Rest] ? IsEqual<First,U> extends true  ? true : Includes<Rest,U> : false```

Solution by HelloWook #36366

type Includes<T extends readonly any[], U> = T extends [infer First, ...infer Rest] ? Equal<First, U> extends true
? true
: Includes<Rest, U>
: false

Solution by asylbekduldiev #36289

// 你的答案
type Includes<T extends readonly any[], U> = T extends [infer P, ...infer Rets] ? (Equal<P, U> extends true ? true : Includes<Rets, U>): false

Solution by reonce #36049

type Includes<T extends readonly any[], U> = T extends [infer FirstEl, ...infer RestEl]
  ? Equal<FirstEl, U> extends true
      ? true
      : Includes<RestEl, U>
  : false;

Solution by karazyabko #36031

type Includes<T extends readonly any[], U> = T extends [infer First, ...infer Rest] ? Equal<First, U> extends true ? true : Includes<Rest, U> : false;

Solution by codingaring #35941

// 你的答案
// 方法1：将数组做映射，再将U作为key取出来，但它无法通过全部的测试用例
type Includes<T extends readonly any[], U> = {
  [key in T[number]]: true
}[U] extends true ? true : false

// 方法2：递归调用isEqual方法

type isEqual<A,B> = (<K>() => K extends A ? 1: 0) extends (<K>() => K extends B ? 1: 0) ? true : false
// type res = isEqual<'a', 'a'>
// type res2 = isEqual<'a', 'b'>
// type res3 = isEqual<true, boolean>
// type res4 = isEqual<null, undefined> // false
// type res5 = isEqual<undefined, null> // false

type Includes<T extends readonly any[], U> =  T extends [T[0], ...infer Rest] ?  isEqual<T[0], U> extends true ? true : Includes<Rest, U> : false

Solution by naruto-823 #35794

type Includes<T extends string[], S> = S extends keyof T[number] ? true : false;

Solution by Sensuele #35778

// 你的答案
type Includes<T extends any[], U> = U extends T[number] ? true : false

Solution by ndwgg #35547

type Includes<T extends readonly any[], U> =  { [P in keyof T ]: Equal<T[P], U> extends true ? true : false } extends { [key: number]: false } ? false : true;

Solution by gangnamssal #35491

export type FirstExpression<X> = <T>() => T extends X ? 1 : 2;
export type SecondExpression<Y> = <P>() => P extends Y ? 1 : 2;
export type MyEqual<X, Y> = FirstExpression<X> extends SecondExpression<Y> ? true : false;

type Includes<T extends readonly any[], U> = true extends {
  [I in keyof T]: MyEqual<T[I], U>
}[number] ? true : false

Solution by RanungPark #35442

// your answers
type setup = ["Kars", "Esidisi", "Wamuu", "Santana"];

type Includes<T extends unknown[], U> = U extends T[number] ? true : false;

const firstData: Includes<setup, "Dio"> = false;
const trueData: Includes<setup, "Kars"> = true;

Solution by Sathiyapramod #35417

/**
Returns a boolean for whether given two types are equal.
@link https://github.com/microsoft/TypeScript/issues/27024#issuecomment-421529650
*/
type IsEqual<T, U> = (<G>() => G extends T ? 1 : 2) extends <G>() => G extends U
    ? 1
    : 2
    ? true
    : false;

type Includes<Value extends any[], Item> = Value extends [
    infer First,
    ...infer Rest
]
    ? IsEqual<First, Item> extends true
        ? true
        : Includes<Rest, Item>
    : false;

Solution by gyeounjeong #35360

type MyEqual<X, Y> =
  (<T>() => T extends X ? 1 : 2) extends
  (<T>() => T extends Y ? 1 : 2) ? true : false
type Includes<T extends readonly any[], U> = T extends [] ? false :
  MyEqual<T[0], U> extends true
  ? true
  : T extends [infer f, ...infer rest]
  ? Includes<rest, U>
  : false;

Solution by watanaki #35195