TypeScript:将键值类型反向映射到值键

Question

给定一个类型的对象:

type Key2Value = {
  foo: "bar"
  voo: "doo"
}

假设该类型的值始终为字符串类型，如何构造实用类型ReverseMap<T>反向映射键值对到值键对？

type Value2Key = ReverseMap<Key2Value>
// yields:
type Value2Key = {
  bar: "foo"
  doo: "voo"
}

Answer 1

type Key2Value = {
  foo: "bar"
  voo: "doo"
}

type ReverseMap<T extends Record<keyof T, keyof any>> = {
    [P in T[keyof T]]: {
        [K in keyof T]: T[K] extends P ? K : never
    }[keyof T]
}

type Value2Key = ReverseMap<Key2Value>

Playground