enums.md

This is a very early stage 0 exploration to add enums to Javascript, as a syntatic simplication over a common pattern to define enumerations.

Introduction

Enums come up often in code bases (TODO: try to estimate a number) and it is easy to get it incorrectly. Specifically, it is easy to forget:

• to Object.freeze the object
• to declare it as a const which avoids having the symbol redefined

With this in mind, we propose a nem keyword to javascript, say enum which de-sugars to the following:

// if you write this ...
enum Foo {
  BAR: 1,
  HELLO "hello",
  WORLD: false
}

// ... it gets de-sugared to:
const Foo = Objec.freeze({
  BAR: 1,
  HELLO: "hello",
  WORLD: false
});

// TODO(goto): should we use Symbols here for extra type safety?

• http://2ality.com/2016/01/enumify.html
• https://stackoverflow.com/questions/287903/enums-in-javascript
• https://www.typescriptlang.org/docs/handbook/enums.html

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