type-challenges solution ( hard )

[jiangshanmeta]

type-challenges

原项目地址

55・Union to Intersection

type UnionToIntersection<U> = (U extends any? (a:U)=>void : never) extends (a:infer T)=>void ? T:never

57・Get Required

type FilterRequiredKey<T,K extends keyof T> = T extends {
  [k in K]-?:T[k]
}? K :never;

type GetRequired<T> = {
  [K in keyof T as FilterRequiredKey<T,K>]:T[K]
}

59・Get Optional

type FilterOptionalKey<T,K extends keyof T> = T extends {
  [k in K]-?:T[k]
}? never:K;

type GetOptional<T> = {
  [K in keyof T as FilterOptionalKey<T,K>]:T[K]
}

89・Required Keys

type RequiredKeys<T , K = keyof T> = K extends keyof T ? 
    T extends Required<Pick<T,K>> ? K : never
    :never

90・Optional Keys

type OptionalKeys<T,K = keyof T> = K extends keyof T?
  T extends Required<Pick<T,K>>?never:K
  :never;

112・Capitalize Words

type CapitalizeWords<S extends string> = Capitalize<
  CapitalizeSeparator< CapitalizeSeparator<CapitalizeSeparator<S,' '>,','> ,'.' >
>

type CapitalizeSeparator<T extends string,S extends string> = T extends `${infer F}${S}${infer L}`?
  `${Capitalize<F>}${S}${Capitalize<CapitalizeSeparator<L,S>>}`:T

114・CamelCase

type CamelCase<S extends string,S1 = Lowercase<S>> = S1 extends `${infer F}_${infer R}`?`${F}${Capitalize<CamelCase<R>>}`:S1

147・C-printf Parser

type ControlsMap = {
  c: 'char',
  s: 'string',
  d: 'dec',
  o: 'oct',
  h: 'hex',
  f: 'float',
  p: 'pointer',
}

type ParsePrintFormat<S extends string,T extends string[] = []> = S extends `${infer F}%${infer K}${infer R}`?
  K extends keyof ControlsMap?
    ParsePrintFormat<R,[...T,ControlsMap[K]]>
    :ParsePrintFormat<R,T>
  :T

223・IsAny

type IsAny<T> = 0 extends (1&T) ? true:false

300・String to Number

type Make10<T extends any[]> = [
  ...T,
  ...T,
  ...T,
  ...T,
  ...T,
  ...T,
  ...T,
  ...T,
  ...T,
  ...T,
]

type Make1<S extends string,T extends any[] = []> = `${T['length']}` extends S?T:Make1<S,[0,...T]>

type ToTuple<S extends string,T extends any[] = []> = S extends `${infer F}${infer R}`?ToTuple<R,[...Make10<T>,...Make1<F>]>:T

type ToNumber<S extends string> = ToTuple<S>['length']

399・Tuple Filter

type FilterOut<T extends any[], F> = T extends [infer I,...infer R]?
  [I] extends [F] ? FilterOut<R,F>: [I,...FilterOut<R,F>]
  :[]

472・Tuple to Enum Object

type Tuple2Object1<T extends readonly any[]> = {
  readonly [K in T[number] as Capitalize<K>]:K
}

type Copy<T> = {
  [K in keyof T]:T[K]
}

type Tuple2Object2<T extends readonly any[],C extends any[] = []> = T extends readonly [infer F,...infer R]?
  {
    readonly [K in (F&string) as Capitalize<K> ]:C['length']
  } & Tuple2Object2<R,[...C,0]>
  :{}

type Enum<T extends readonly string[], N extends boolean = false> = N extends false ? Tuple2Object1<T>:Copy<Tuple2Object2<T>>

651・Length of String 2

type LengthOfString<S extends string,C extends number[] = []> = S extends `${infer F0}${infer F1}${infer F2}${infer F3}${infer F4}${infer F5}${infer F6}${infer F7}${infer F8}${infer F9}${infer R}`? LengthOfString<R,[...C,0,1,2,3,4,5,6,7,8,9]>
  : S extends `${infer F}${infer R}`?
    LengthOfString<R,[...C,0]>
    :C['length']

847・String Join

type Join<
  T extends any[], 
  U extends string | number,
  R extends string = ''
> = 
  T extends [infer F,...infer L]?
    L['length'] extends 0?
      `${R extends ''?'':`${R}${U}`}${F&string}`
      :Join<L,U,`${R extends ''?'':`${R}${U}`}${F&string}`>
  :R
declare function join<U extends string>(delimiter: U): <T extends string[]>(...parts: T) => Join<T,U>;

956・DeepPick

type DeepPick<T extends Record<string,any>, U extends string> = (U extends string? 
  U extends `${infer F}.${infer R}`?
    (arg:{
      [K in F]:DeepPick<T[F],R>
    })=>void
    :U extends keyof T?
      (arg:Pick<T,U>)=>void
      :(arg:unknown)=>void
  :never
  
  ) extends (arg:infer Z)=>void? Z:never;

1383・Camelize

type CamelizeWord<T extends string> = T extends `${infer F}_${infer L}`?`${F}${Capitalize<L>}`:T

type Camelize<T> = T extends any[]?
    T extends [infer F,...infer R]?
      [Camelize<F>,...Camelize<R>]
    :[]
  :
  T extends Record<string,any>?
    {
      [K in keyof T as CamelizeWord<K&string>]:Camelize<T[K]>
    }

  :T

2095・Drop String

type DropOne<S extends string,R extends string> = S extends `${infer A}${R}${infer B}`?
  DropOne<`${A}${B}`,R>
  :S

type DropString<S extends string, R extends string> = R extends `${infer F}${infer L}`?
  DropString<DropOne<S,F>,L>
  :S

2822・Split

type NormalSplit<S extends string, SEP extends string> = S extends `${infer F}${SEP}${infer R}`?[
  F,
  ...Split<R,SEP>
]:[S]

type StringToTuple<S extends string> = S extends `${infer F}${infer R}`?[F,...StringToTuple<R>]:[] 

type Split<S extends string, SEP extends string> = string extends S?
  string[]
  :SEP extends ''?
    StringToTuple<S>
    :NormalSplit<S,SEP>

2828・ClassPublicKeys

解法一：

type ClassPublicKeys<T extends any,K = keyof T> = K extends keyof T? T extends Pick<T,K>?K:never : never;

解法二：

type ClassPublicKeys<A> = keyof A

2857・IsRequiredKey

type IsRequiredKey<T, K extends keyof T> = (K extends keyof T?  
  T extends Required<Pick<T,K>>?true:false
  :never) extends true?true:false;

2949・ObjectFromEntries

解法1:

type Copy<T> = {
  [K in keyof T]:T[K]
}

type ObjectFromEntries<T extends [string,any]> = Copy<(T extends any? (arg:{
  [K in T[0]]:T[1]
})=>void:never) extends (arg:infer U)=>void ?U:never>;

解法2:

type ObjectFromEntries<T extends [string,any]> = {
  [K in T as K[0]]:K[1]
}

4037・IsPalindrome

type StringToTuple<T extends string> = T extends `${infer F}${infer R}`? [F,...StringToTuple<R>]:[];

type IsIsPalindromeArray<T extends any[]> = T extends [infer F,...infer M,infer L] ? 
  F extends L?IsIsPalindromeArray<M>:false
  :true;

type IsPalindrome<T extends string | number> = IsIsPalindromeArray<StringToTuple<`${T}`>>

5423・Intersection

type ToUnion<T> = T extends any[]? T[number]:T;

type Intersection<T extends any[],R = ToUnion<T[0]>> = T extends [infer F,...infer L]? Intersection<L,R & ToUnion<F>>:R

6141・Binary to Decimal

type BinaryToDecimal<
  S extends string,
  R extends any[] = []
> = 
  S extends `${infer F}${infer L}`?
    F extends '0'? BinaryToDecimal<L,[...R,...R]>:BinaryToDecimal<L,[...R,...R,1]>
    :R['length']

7258・Object Key Paths

type GenNode<K extends string | number,IsRoot extends boolean> = IsRoot extends true? `${K}`: `.${K}` | (K extends number? `[${K}]` | `.[${K}]`:never)

type ObjectKeyPaths<
  T extends object,
  IsRoot extends boolean = true,
  K extends keyof T = keyof T
> = 
K extends string | number ?
  GenNode<K,IsRoot> | (T[K] extends object? `${GenNode<K,IsRoot>}${ObjectKeyPaths<T[K],false>}`:never)
  :never;