How to reverse typing on a typescript enum?

问题

Given an enum in typescript

enum CoffeeSizes {
  Large = 'L',
  Medium = 'M',
  ExtraLarge = 'XL',
}

CoffeeSizes.Large === 'L' // true

How do I do the reverse lookup, where I can say

CoffeeSizes.L === 'Large'

How can I create a type with the inverse enum?

回答1:

Reverse mappings are only possible for numeric non const enums.
As in the example below

enum CoffeeSizes {
  Large,
  Medium,
  ExtraLarge
}

const nameOffLargeCoffeeSize = CoffeeSizes[CoffeeSizes.Large];
CoffeeSizes[nameOffLargeCoffeeSize] === CoffeeSizes.Large;

You can get more details in TypeScript docs

来源：https://stackoverflow.com/questions/57966858/how-to-reverse-typing-on-a-typescript-enum