JavaScript enum function with working JSDoc autocompletion

enum.js

/**
 * @description
 * Creates a frozen enumeration object where each key maps to its own string value.
 * This is useful for defining a set of constant string values that can be referenced by name.
 * This also avoids defining an object with duplicated string values manually.
 * @template {string} T
 * @param {...T} values
 * @returns {{ [K in T]: K }}
 * @example
 * const Colors = Enum('Red', 'Green', 'Blue');
 * console.log(Colors.Red); // "Red"
 */
function Enum(...values) {
  // remove prototype's base functions/variables (credit @bayorm)
  const result = Object.create(null);

  for (const key of values) {
    result[key] = key;
  }

  return Object.freeze(result);
}

// Usage
const Colors = Enum('Red', 'Green', 'Blue');
console.log(Colors.Red); // "Red"

const result = Object.create(null) removes protos

const result = Object.create(null) removes protos

@bayorm Didn't know that, thanks, fixed !

Here is typescript version with type-level immutability, if you think freeze is expensive:

export function Enum<const T extends readonly string[]>(
  ...values: T
): Readonly<{ [K in T[number]]: K }> {
  const result = Object.create(null) as { [K in T[number]]: K };

  values.forEach((key: T[number]) => {
    result[key] = key;
  });

  return result;
}