Type Challenges: 02757-medium-partialbykeys Solution

// your answers
type Intersection<T> = { 
  [K in keyof T]: T[K]
}

type PartialByKeys<T, K extends keyof T =keyof T> = Intersection<{
  [X in Exclude<keyof T, K>]: T[X]
} & {
  [X in K]?: T[X]
}>

Solution by gobielJonathan #34527

type PartialByKeys<T, K extends keyof T = never> = [K] extends [never] ? Partial<T> : Obj<{
  [P in keyof T as P extends K ? P : never]?: T[P]
} & Omit<T, K>>

Solution by ouzexi #34049


type PartialByKeys<T, K extends keyof T = keyof T> = 
Partial<Pick<T,K>> & Omit<T,K> extends infer G
 ? Pick<G,keyof G>:never

这样就行了

Solution by xdrlmm #33948

// 你的答案

type PartialByKeys<T, K extends string | number | symbol = keyof T> = { [ i in keyof PartialByKeys2<T, K> ] : PartialByKeys2<T, K>[i] }

type s = PartialByKeys

type PartialByKeys2<T, K extends string | number | symbol> = { [i in keyof T as i extends K ? never : i]: T[i] } & { [i in K]?: K extends keyof T ? T[i] : never } why is wrong?

Solution by zhangshuaiqiang11 #33882

type PartialByKeys<T, K extends keyof T = keyof T> = Omit<{
  [key in Extract<keyof T,K>]?: T[key]
} & {
  [key in Exclude<keyof T,K>]: T[key]
}, never>

Solution by kana-chan #33177

type PartialByKeys<T, K extends keyof T = keyof T> = Omit<Partial<Pick<T, K>> & Omit<T, K> , never>

Solution by iwebexpert #32590

type Cast<T> = { [K in keyof T]: T[K] }
type PartialByKeys<T extends object, K extends keyof T = keyof T> = Cast<{ [P in keyof T as P extends K ? P : never]?: T[P]} & Omit<T, K>>

억지로 value의 undefined 타입이 제거되도록 Cast 타입을 사용했지만 사용하지 않는 쪽이 더 나은거 같다. 문제가 조금 옛날 것인거 같다.

Solution by dev-hobin #32495

type MakePartial<T> = {
  [P in keyof T]?: T[P]
}

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

type PartialByKeys<T extends {}, K extends keyof T = keyof T> = [K] extends [''] ? MakePartial<T> : Flatten<Omit<T, K> & MakePartial<Pick<T, K>>>

Solution by keyurparalkar #32328

type PartialByKeys<T, U extends keyof T = keyof T> = Omit<Partial<Pick<T, U>> & Omit<T, U>, never>;

上面的版本和下面的版本是等价的，仅仅使用 Utility Type 的方法更简洁

type MergeType<O> = {
  [P in keyof O]: O[P];
};
type PartialByKeys<T, K extends keyof T = keyof T> = MergeType<
  { [R in keyof T as R extends K ? R : never]?: T[R] } & Omit<T, K>
>;

其中

Omit<T,never> 的效果和 type MergeType<O> 效果是的。
Partial<Pick<T, U>> 和 { [R in keyof T as R extends K ? R : never]?: T[R] } 效果是等价的

Solution by vangie #32172

// your answers
type PartialByKeys<T, U> = { [K in keyof T as K extends U ? U : never]?: T[K] } & { [K in keyof T as K extends U ? never : K]: T[K] } extends infer I ? { [K in keyof I]: I[K] } : never

Solution by sunvictor #31650

// your answers
type Duplicate<T> = { [P in keyof T]: T[P]; }
type PartialByKeys<T, K extends keyof T = keyof T> = Duplicate<Partial<Pick<T, K>> & Omit<T, K>>

Solution by wzc520pyfm #31482

// your answers
type Merge<T> = {
  [K in keyof T]: T[K]
}
type PartialByKeys<T, K = keyof T> = Merge<Partial<Pick<T,K & keyof T>> & Omit<T, K & keyof T>>;

Solution by kangaroona #31151

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

type PartialByKeys<T, K extends keyof T = keyof T> = IntersectionToObj<Partial<Pick<T, K>> & Omit<T, K>>;

Solution by kai-phan #30925

type Unify<T> = {
  [Key in keyof T]: T[Key]
}
type PartialByKeys<T, K extends keyof T = keyof T> = Unify<{
   [Key in K]?: T[Key]
} & {
   [Key in Exclude<keyof T, K>]: T[Key]
}>

Solution by maximallain #30867

type PartialByKeys<T, K extends keyof T = keyof T> = Omit<{
  [Key in keyof T as Key extends K ? Key : never]?: T[Key]
} & {
  [Key in Exclude<keyof T, K>]: T[Key]
}, never>

Solution by matallui #30805

// your answers
type PartialByKeys<T, K extends keyof T = keyof T> = Omit<{[Key in K]?: T[Key]} & Omit<T, K>, never>;

Surprisingly didn't find someone submitted this

Solution by orl0 #30744

type PartialByKeys<T, K extends keyof T = keyof T> = Omit<{
  [U in keyof T as U extends K ? never : U]: T[U]
} & {
   [U in keyof T as U extends K ? U : never]?: T[U]
}, never>

Solution by dreamluo-plus #30583

type Intersection<T> = {
  [S in keyof T]: T[S]
}

type PartialByKeys<T, K extends keyof T = keyof T> = Intersection<{
  [S in keyof T as S extends K ? S : never]?:T[S]
} &{
  [S in keyof T as S extends K ? never: S] : T[S]
}>

Solution by Yoon-Hae-Min #30510

// 大部分解答不能捕获传入的key 在 T上不存在, 用下面的实现则可以

type MyExclude<T, U> = T extends U ? never : T

type MergeInterface<T> = {
  [P in keyof T ]: T[P]
}

type PartialByKeys<T, K = never> = [K] extends [never] ? {
  [P in keyof T ]?: T[P]
} : [MyExclude<K, keyof T>] extends [never] ? MergeInterface<{
  [P in keyof T as P extends K ? never : P]: T[P]
} & {
  [P in keyof T as P extends K ? P : never]?: T[P]
}> : never

Solution by xiahouwei #30380

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

type Partial<T> = {
  [P in keyof T]?: T[P]
}

type Extract<T, K> = {
  [P in keyof T as P extends K ? P : never]?: T[P]
}

type Exclude<T, K> = {
  [P in keyof T as P extends K ? never : P]: T[P]
}

type PartialByKeys<T, K = any> = Assemble<Partial<Extract<T, K>> & Exclude<T, K>>

Solution by tclxshunquan-wang #29802

type PartialByKeys<T, E extends keyof T = keyof T> = {
    [k in E]?: T[k]
} & {
    [k in keyof T as k extends E ? never: k]: T[k]
};


type User = PartialByKeys<{
    name: string;
    age: number;
    address: string;
}, 'name'>;


const user: User = {
    age: 1,
    address: ''
}

Solution by sundial-dreams #29484

Solution:

type Merge<T, U> = Pick<T & U, keyof (T & U)>;

type PartialByKeys<T, K = keyof T> = Merge< Pick<Partial<T>, Extract<keyof T, K>>,  Pick<T, Exclude<keyof T, K>> >

Solution by DmitriiBr #29354

// your answers

// your answers
type GenerateNewType<T> = {
  [K in keyof T]: T[K];
};

type PartialByKeys<T, K extends keyof T = keyof T> = GenerateNewType<{
  [U in keyof T as U extends K ? U : never]?: T[U];
} & {
  [U in keyof T as U extends K ? never : U]: T[U];
}>

Solution by kerolossamir165 #29210

type PartialByKeys<O, K extends keyof O> = { [P in K]?: O[P] } & { [P in keyof O as P extends K ? never : P]: O[P] }

Solution by sunhk123456 #28954

/**
 * Partial<Pick<T, K>> 取出需要Partial的key
 * Omit<T, K> 排除需要Partial的key
 * 此时两个类型是Intersection type,不符合Equal校验,利用Omit一个never key将两个类型合并一次
 * 或者遍历一遍这个Intersection type
 */

type PartialByKeys<T, K extends keyof T = keyof T> =
  Omit<
    Partial<Pick<T, K>> & Omit<T, K>
    , never
  >

// type PartialByKeys<T, K extends keyof T = keyof T> = IntersectionToObj<
//   Partial<Pick<T, K>> & Omit<T, K>
// >
// type IntersectionToObj<T> = {
//   [K in keyof T]: T[K]
// }

Solution by rodrick278 #28933

type PartialByKeys<T, K extends keyof T = keyof T> = Omit<{
  [Key in keyof T as Exclude<Key,K>]:T[Key]
}&{
  [Key in K]?:T[Key]
},never>

Solution by DoubleWoodLin #28693

Use Omit version: type PartialByKeys<T, K extends keyof T = keyof T> = Omit< Omit<T, K> & Partial<Pick<T, K>>, never

;

Solution by DoubleWoodLin #28692

type PartialByKeys<T, K extends keyof T = keyof T> = Omit<Omit<T, K> & Partial<Pick<T, K>>, never>

Solution by jjswifty #27626

// your answers
type IntersectionToObj<T> = {
  [K in keyof T] : T[K]
}

type PartialByKeys<T, K = any> =  IntersectionToObj<{
  [P in keyof T as P extends K ? P: never]?: T[P]
} & {
  [P in Exclude<keyof T, K>] : T[P]
}>

Solution by GreattitJY #27405

// your answers
type IntersectionToObject<T> = {
  [P in keyof T]: T[P]
}

type PartialByKeys<T extends {}, K extends keyof T = keyof T> = IntersectionToObject<{
  [P in keyof T as P extends K ? P : never]?: T[P]
} & {
  [P in keyof T as P extends K ? never: P]: T[P]
}>

Solution by daiki-skm #27393