TypeScript 杂记九《Integers Comparator》

Integers Comparator

思路

参考这篇文章中的思路：TypeScript 杂记五《Sort》

完整示例


type Reverser<T> = T extends 1 ? -1 : T extends 0 ? 0 : 1

type StringToArray<T extends string, RR extends string[] = []> = T extends `${infer L}${infer R}`
  ? StringToArray<R, [...RR, L]>
  : RR

type Compare<A, B, H extends unknown[] = []> = `${H['length']}` extends A
  ? `${H['length']}` extends B
    ? 0
    : -1
  : `${H['length']}` extends B
  ? 1
  : Compare<A, B, [...H, unknown]>

type CompareArrayHelper<A, B> = A extends [infer AL, ...infer AR]
  ? B extends [infer BL, ...infer BR]
    ? Compare<AL, BL> extends 0
      ? CompareArrayHelper<AR, BR>
      : Compare<AL, BL>
    : 0
  : 0

type CompareArray<
  A extends string[],
  B extends string[],
  H extends unknown[] = [],
> = H['length'] extends A['length']
  ? H['length'] extends B['length']
    ? CompareArrayHelper<A, B>
    : -1
  : H['length'] extends B['length']
  ? 1
  : CompareArray<A, B, [...H, unknown]>

type ComparatorHelper<A extends string, B extends string> = A extends `-${infer _A}`
  ? B extends `-${infer _B}`
    ? Reverser<CompareArray<StringToArray<_A>, StringToArray<_B>>>
    : -1
  : B extends `-${string}`
  ? 1
  : CompareArray<StringToArray<A>, StringToArray<B>>

type Comparator<A extends number | bigint, B extends number | bigint> = ComparatorHelper<
  `${A}`,
  `${B}`
> extends 1
  ? Comparison.Greater
  : ComparatorHelper<`${A}`, `${B}`> extends 0
  ? Comparison.Equal
  : Comparison.Lower

测试


type Test1 = Comparator<1, 2> // Comparison.Lower
type Test11 = Comparator<1, -2222> // Comparison.Greater
type Test111 = Comparator<-1, -2> // Comparison.Greater
type Test2 = Comparator<1_000_000_000_000n, 1_000_000_000_000n> // Comparison.Equal
type Test3 = Comparator<1_000_000_000_000n, 1_000_000_000_001n> // Comparison.Lower
type Test4 = Comparator<1_000_000_000_100n, 1_000_000_000_001n> // Comparison.Greater
type Test5 = Comparator<-1_000_000_000_100n, -1_000_000_000_001n> // Comparison.Lower