Retrieve all values of a specific enum type in TypeScript

Question

Retrieve all values of a specific enum type in TypeScript

When working with Typescript, I am looking to retrieve all values of an enum type and store them in an array. In C#, a similar method would look like this:

public static TEnum[] GetValues<TEnum>() where TEnum : Enum
{
    return Enum.GetValues(typeof(TEnum))
        .OfType<TEnum>()
        .ToArray();
}

How can we achieve the same functionality in Typescript? Ideally, the usage would resemble:

const allColors: Color[] = GetEnumValues<Color>();

Just for reference, I am using Typescript version 3.9.4 but open to suggestions for newer versions.

typescript

Answer 1

Answer №1

It's quite simple to achieve. The only limitation is that you cannot use it with const enum. Typescript will generate an error if you attempt to do so, as it is not available at runtime.

function getEnumValues<T>(en: any): T[] { // perhaps it can be accomplished without using any, but I am unsure
   return Object.keys(en)
     .filter(k => !isFinite(Number(k))) // this filters out the reverse mappings: https://www.typescriptlang.org/docs/handbook/enums.html#reverse-mappings
     .map(k => en[k]);
}

For further reference, consider the following example: https://stackblitz.com/edit/typescript-z2swch

Answer 2

It's quite simple to achieve. The only limitation is that you cannot use it with const enum. Typescript will generate an error if you attempt to do so, as it is not available at runtime.

function getEnumValues<T>(en: any): T[] { // perhaps it can be accomplished without using any, but I am unsure
   return Object.keys(en)
     .filter(k => !isFinite(Number(k))) // this filters out the reverse mappings: https://www.typescriptlang.org/docs/handbook/enums.html#reverse-mappings
     .map(k => en[k]);
}

For further reference, consider the following example: https://stackblitz.com/edit/typescript-z2swch

Retrieve all values of a specific enum type in TypeScript

Answer №1

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