JavaScript Implementing Enums Using Symbols


As ES6 introduced Symbols, which are both unique and immutable primitive values that may be used as the key of an Object property, instead of using strings as possible values for an enum, it's possible to use symbols.

// Simple symbol
const newSymbol = Symbol();
typeof newSymbol === 'symbol' // true

// A symbol with a label
const anotherSymbol = Symbol("label");

// Each symbol is unique
const yetAnotherSymbol = Symbol("label");
yetAnotherSymbol === anotherSymbol; // false

const Regnum_Animale    = Symbol();
const Regnum_Vegetabile = Symbol();
const Regnum_Lapideum   = Symbol();

function describe(kingdom) {

  switch(kingdom) {

    case Regnum_Animale:
        return "Animal kingdom";
    case Regnum_Vegetabile:
        return "Vegetable kingdom";
    case Regnum_Lapideum:
        return "Mineral kingdom";


// Vegetable kingdom

The Symbols in ECMAScript 6 article covers this new primitive type more in detail.