type Flip<T> = {
  [K in keyof T as T[K] extends string | number | boolean ? `${T[K]}` : never]: K 
}

Solution by kai-phan #32519

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

Solution by rkamely #32105

type Flip<T> = {
  [K in keyof T as `${T[K]}`]: K
}

Solution by Zhen-code #31995

有趣，得益于ts的模板字符串

type Flip<T extends Record<string, any>> = {
  [P in keyof T as `${T[P]}`]: P;
};

Solution by sunsunmonkey #31540

type Flip<T extends Record<string, string | number | boolean>> = {
  [P in keyof T as `${T[P]}`]: P
}

Solution by MyeonghoonNam #31054

type Flip<T extends Record<string, string | number | boolean>> = {
  [K in keyof T as `${T[K]}`]: K
}

Solution by yang49519845 #30182

type ObjectKey<T extends object, K extends keyof T, V> = K extends keyof T ? T[K] extends V ? K : never : never

type Flip<T extends object> = {
  [P in T[keyof T] as P extends string | number | symbol ? P : `${P}`]: ObjectKey<T, keyof T, P>
}

Solution by zhangqiangzgz #30175

type Flip<T> = {
  [P in keyof T as T[P] extends string | boolean | number | bigint | null | undefined ? `${T[P]}`: never]: P
}

Solution by 8471919 #30102

type Flip<T> = {
  [P in keyof T as T[P] extends string | number | symbol
    ? T[P]
    : T[P] extends boolean | bigint | null | undefined
    ? `${T[P]}`
    : never]: P;
};

Solution by DoGukKim #29168

type Flip<T extends Record<keyof any, any>> = {
  [K in keyof T as T[K] extends number | symbol
    ? T[K]
    : `${T[K]}` extends `${infer Key}`
    ? Key
    : never]: K;
};

Solution by DoubleWoodLin #28721

type Fibonacci<
  T extends number,
  R extends any[] = [[""]],
  C extends any[] = [""]
> = C["length"] extends T
  ? R extends [...infer F, infer RES extends any[]]
    ? RES["length"]
    : never
  : Fibonacci<
      T,
      R extends [infer D extends any[], infer M extends any[]]
        ? [M, [...D, ...M]]
        : [["1"], ["1"]],
      [...C, ""]
    >

Solution by duanbx #28633

// your answers
type Flip<T extends {}> = { [K in keyof T as `${T[K]}`]: K }

Solution by AAA611 #27897

// your answers
type Flip<T extends {[key: string|number]:  string|number|boolean}> = {
  [K in keyof T as T[K] extends string|number ? T[K] : `${T[K]}`]: K
}

Solution by Take0518 #27801

type Flip<T> = T extends {[P in any]: any} ? {[K in keyof T as `${T[K]}`]: K} : T

Solution by HenrryShaw #27781

type Flip<T extends Record<PropertyKey, string | number | boolean>> = {
  [K in keyof T as `${T[K]}`]: K
}

Solution by jjswifty #27650

type Flip<T extends { [key: string]: any }> = {
  [key in keyof T as `${T[key]}`]: key
}

Solution by jiechliu #27504

type Keys = string | boolean | number | undefined | null | bigint

type Flip<T extends Record<PropertyKey, Keys>> = {
  [K in keyof T as `${T[K]}`]: K
}

Solution by RainbowIsPerfect #27424

type Flip<T extends Record<PropertyKey, any>> = { 
    [K in keyof T as T[K] extends PropertyKey 
        ? T[K] 
        : `${T[K]}`
    ]: K;
};

Solution by Azoraqua #27261

// your answers
type Flip<T extends { [key: PropertyKey]: any }> = {
  [key in keyof T as T[key] extends PropertyKey ? T[key] : `${T[key]}`]: key
};

Solution by CheolMinBae #27036

type Flip<T extends Record<string, any>> = { [K in keyof T as `${T[K]}`]: K }

Solution by smileboyi #26983

type Flip<T extends Record<string, string | number | boolean>> = {
  [K in keyof T as `${T[K]}`]: K;
};

Solution by ryuji-1to #26929

// type Flip<T extends {[key: string | number | symbol] : any }> = {[K in keyof T as T[K] ] : K } // true: 'bool'  
type Flip<T extends {[key: string | number | symbol] : any }> = {[K in keyof T as `${T[K]}` ] : K }

Solution by jsujeong #26925

type GetValues<T> = T extends { [P in keyof T]: infer R } ? R : never;

type GetKeyOfValue<T, U> = keyof T extends infer R extends keyof T
  ? R extends string | number | symbol
    ? [T[R]] extends [U]
      ? R
      : never
    : never
  : never;

type Flip<T> = GetValues<T> extends infer Value extends string | number | symbol
  ? { [P in Value]: GetKeyOfValue<T, P> }
  : never;

Solution by rldnd #26867

type Flip<T extends Record<PropertyKey, any>>
 = { [Key in keyof T as T[Key] extends PropertyKey ? T[Key] : `${T[Key]}`] : Key }

Solution by tokyo9pm #26731

type Flip<T extends Record<PropertyKey, any>> = { [K in keyof T as ${T[K]}]: K }

Solution by HaoxueAllen #26557

type Flip<TObject extends Record<string | number | symbol, unknown>> = {
  [Key in keyof TObject as TObject[Key] extends boolean | string | number
    ? `${TObject[Key]}`
    : never]: Key
}

Solution by valentynpodkradylin #26232

type Flip<T extends Record<any, any>> = {
  [key in keyof T as `${T[key]}`]: key
}

Solution by fleeze #26022

type Flip<T extends object> = {
  [k in keyof T as `${T[k]}`]: k
} 

Solution by kanishev #25916

// your answers
type Flip<T extends Record<PropertyKey, string | number | boolean>> = {
  [k in keyof T as `${T[k]}`]: k
}

Solution by kiki-zjq #25218

type Flip<T extends Record<PropertyKey, string | number | boolean>> = {
  [key in keyof T as `${T[key]}`]: key;
}

Solution by yungo1846 #24823