TypeScriptの型で世界のナベアツ

nabeatsu.d.ts

type Natural = 0[];
type Zero = [];
type One = [0];
type AhoSuffix = '（アホ）';
type Length<Array extends unknown[]> = Extract<Array['length'], number>;

type Add<N1 extends Natural, N2 extends Natural> = [...N1, ...N2];
type AddNum<N1 extends number, N2 extends number> = Length<[...NumToNat<N1>, ...NumToNat<N2>]>;
type Sub<N1 extends Natural, N2 extends Natural> = N1 extends [...N2, ...infer M]
    ? M
    : never;

type IsStrictlySmaller<N1 extends Natural, N2 extends Natural> = Sub<N1, N2> extends never
    ? true
    : false;
type IsDivisible<N1 extends Natural, N2 extends Natural> = N1 extends Zero
    ? true
    : IsStrictlySmaller<N1, N2> extends true
        ? false
        : IsDivisible<Sub<N1, N2>, N2>;

type NatToNum<N extends Natural> = Length<N>;
type NumToNat<N extends number, M extends Natural = []> = Length<M> extends N
    ? M
    : NumToNat<N, Add<M, One>>;

type IsIncludeThree<N extends number> = `${N}` extends `${infer _N}${3}${infer _M}`
    ? true
    : false;
type IsMultipleOfThree<N extends number> = IsDivisible<NumToNat<N>, NumToNat<3>>;
type IsAho<N extends number> = IsIncludeThree<N> extends true
    ? true
    : IsMultipleOfThree<N> extends true
        ? true
        : false;

type Aho<N extends number> = IsAho<N> extends true
    ? `${N}${AhoSuffix}`
    : `${N}`;

type AhoRange<L extends number, Result extends string[] = []> = Length<Result> extends L
    ? Result
    : AhoRange<L, [...Result, Aho<AddNum<Length<Result>, 1>>]>

type Aho1 = Aho<1>;   // '1'
type Aho3 = Aho<3>;   // '3（アホ）'
type Aho5 = Aho<5>;   // '5'
type Aho9 = Aho<9>;   // '9（アホ）'
type Aho10 = Aho<10>; // '10'
type Aho13 = Aho<13>; // '13（アホ）'

type Aho1_50 = AhoRange<50>;
    // ['1', '2', '3（アホ）', '4', '5', '6（アホ）', '7', '8', '9（アホ）', '10', '11', '12（アホ）', '13（アホ）', '14', '15（アホ）', '16', '17', '18（アホ）', '19', '20', '21（アホ）', '22', '23（アホ）', '24（アホ）', '25', '26', '27（アホ）', '28', '29', '30（アホ）', '31（アホ）', '32（アホ）', '33（アホ）', '34（アホ）', '35（アホ）', '36（アホ）', '37（アホ）', '38（アホ）', '39（アホ）', '40', '41', '42（アホ）', '43（アホ）', '44', '45（アホ）', '46', '47', '48（アホ）', '49', '50']