Typescript - 如何正确合并两个包含重叠的枚举？

Question

给定以下枚举：

enum MyFirstEnum {
  A = 'A',
  B = 'B',
  C = 'C'
}

enum MySecondEnum {
  C = 'C',
  D = 'D',
  E = 'E'
}

合并它们的正确方法是什么？ 请注意，它们在键C = 'C'中包含重叠，所以只是MyFirstEnum | MySecondEnum MyFirstEnum | MySecondEnum可能会引起一些麻烦，例如：

type BothEnums = MyFirstEnum | MySecondEnum

const myRecord: Partial<Record<BothEnums, string>> = {}
const someKey = MyFirstEnum.C

myRecord[someKey] = 'some value' // ❌ Property '[MyFirstEnum.C]' does not exist on type 'Partial<Record<BothEnums, string>>'

如果我从这个问题How to merge two enums in TypeScript 中理解正确， Typescript 不能很好地处理具有重复键和值的不同枚举。

但是，如果真的需要将枚举与这种重叠合并，如何在没有（或更少）进一步问题的情况下做到这一点？

Answer 1

那行得通吗？

type BothEnums = {[key in keyof typeof MyFirstEnum | keyof typeof MySecondEnum] : 
  key extends keyof typeof MyFirstEnum ? key extends keyof typeof MySecondEnum ? (typeof MySecondEnum[key]  | typeof MyFirstEnum[key]) :
    typeof MyFirstEnum[key] : key extends keyof typeof MySecondEnum ? typeof MySecondEnum[key] : never} 

相当于：

type BothEnums = {
    A: MyFirstEnum.A;
    B: MyFirstEnum.B;
    C: MyFirstEnum.C | MySecondEnum.C;
    D: MySecondEnum.D;
    E: MySecondEnum.E;
}

需要用 keyof 调用：

const myRecord: Partial<Record<keyof BothEnums, string>> = {}
const someKey1 = MyFirstEnum.C
const someKey2 = MySecondEnum.C

myRecord[someKey1] = 'some value 1' 
myRecord[someKey2] = 'some value 2' 

console.log(JSON.stringify(myRecord)) // "{"C":"some value 2"}" 

但我个人更喜欢这个选项：

const MyFirstEnumDef = ['A','B','C'] as const satisfies readonly string[];
const MySecondEnumDef = ['C','D','E'] as const satisfies readonly string[];
type MyFirstEnum = typeof MyFirstEnumDef[number]
type MySecondEnum = typeof MySecondEnumDef[number]

type BothEnums = MyFirstEnum | MySecondEnum


const myRecord: Partial<Record<BothEnums, string>> = {}
const someKey1 = "C"
myRecord[someKey1] = 'some value 1' 

console.log(JSON.stringify(myRecord)) // "{"C":"some value 1"}"