Enum as Parameter in TypeScript

Question

Isn\'t it possible to set the type of a parameter to an Enum? Like this:

private getRandomElementOfEnum(e : enum):string{
    var length:number = Object.         


        

Answer 1

Summing up the previous answers with some new syntax - a generic typesafe function, which works with numeric enums as well as string enums:

function getRandomElementOfEnum(e: T): T[keyof T] {
  const keys = Object.keys(e);

  const randomKeyIndex = Math.floor(Math.random() * keys.length);
  const randomKey = keys[randomKeyIndex];

  // Numeric enums members also get a reverse mapping from enum values to enum names.
  // So, if a key is a number, actually it's a value of a numeric enum.
  // see https://www.typescriptlang.org/docs/handbook/enums.html#reverse-mappings
  const randomKeyNumber = Number(randomKey);
  return isNaN(randomKeyNumber)
    ? e[randomKey as keyof T]
    : randomKeyNumber as unknown as T[keyof T];
}