2257 - MinusOne

[huangxinrui]

type NumberList = [9, 0, 1, 2, 3, 4, 5, 6, 7, 8];
type ReverseStr<T extends string | number> = (T extends string ? T : ${T}) extends ${infer L}${infer R}
? ${ReverseStr<R>}${L}
: T;
type RemoveFirstZero = T extends ${infer L}${infer R}
? L extends '0'
? R extends ''
? ${T}
: ${RemoveFirstZero<R>}
: T
: never;
type Parse2Int = T extends any
? RemoveFirstZero extends ${infer N extends number}
? N
: never
: never;
type LoopStr = T extends ${infer L extends number}${infer R}
? L extends 0
? ${NumberList[L]}${LoopStr<R>}
: ${NumberList[L]}${R}
: '';
type MinusOne = T extends 0 ? -1 : Parse2Int<ReverseStr<LoopStr<ReverseStr>>>;