A tutorial on efficiently extracting the data type of an enumerated value in TypeScript

enum code {
    x = 10,
    y = 20,
    z = "xyz"
}

I've defined an enum and now I want to create a union type.

type UnionType = 10 | 20 | 'xyz'

Hello, are there any recommendations for achieving this?

Answer №1

In TypeScript 4.8, the introduction of converting string literals to numbers will make it possible for you to achieve this.

type IWantGet = `${code}` extends infer U 
  ? U extends `${infer S extends number}` 
    ? S
    : U 
  : never

// type IWantGet = "abc" | 10 | 20

Playground


Currently, you can only create a union of string literal types.

type IWantGet = `${code}`
// type IWantGet = "10" | "20" | "abc"

Playground

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