JSFiddle - React, Tailwind, and code Playground

JavaScript

class Sizes {
  static Small = new Sizes('small')
  static Medium = new Sizes('medium')
  static Large = new Sizes('large')
  #value
  constructor(value) {
    this.#value = value
  }
  toString() {
    return this.#value
  }
}
const mySize = Sizes.Small
console.log(mySize === Sizes.Small)  // logs true
console.log(mySize instanceof Sizes) // logs true