vite-plugin-better-enums

TypeScript enums are famously problematic — they compile to IIFEs, they block tree-shaking, and they carry a reverse-mapping table you almost never need.

This plugin rewrites export enum declarations at build time into plain named const exports in a virtual module, giving you all the ergonomics of enums with none of the baggage.

// ------------
// Before
// ------------

//#region src/fruit.ts
var Fruit = /* @__PURE__ */ (function (Fruit) {
  Fruit[(Fruit["Apple"] = 0)] = "Apple";
  Fruit[(Fruit["Kiwi"] = 1)] = "Kiwi";
  Fruit[(Fruit["Banana"] = 2)] = "Banana";
  return Fruit;
})({});
//#endregion

//#region src/main.ts
console.log(Fruit.Apple);
console.log(Fruit.Banana);
//#endregion

// ------------
// After
// ------------
console.log(0);
console.log(2);

Usage stays exactly the same:

import { Fruit } from "./fruit";

const pick: Fruit = Fruit.Apple; // 1

---

How it works

// ------------
// input
// ------------
export enum Fruit {
  Apple,
  Kiwi,
  Banana,
}

// ------------
// output (in fruit.ts after transform)
// ------------
import * as Fruit from "\0enum-virtual:/abs/path/fruit.ts::Fruit";
export { Fruit };

// ------------
// generated virtual module
// ------------
export const Apple = 1;
export const Kiwi = 2;
export const Banana = 3;

The bundler then inlines all constants at their use sites, leaving zero runtime overhead.

---

Why

	TypeScript enum	This plugin
Tree-shakeable	✗	✓
Works with isolatedModules	✗	✓
Serializes cleanly to JSON	✗	✓
No reverse-mapping bloat	✗	✓
Familiar import syntax	✓	✓
Type-safe	✓	✓

---

Installation

npm install -D git+https://github.com/eye-wave/better-enums.git

---

Setup

// vite.config.ts
import { defineConfig } from "vite";
import betterEnums from "vite-plugin-better-enums";

export default defineConfig({
  plugins: [betterEnums()],
});

The plugin runs with enforce: "pre" so it transforms your source before esbuild or any other plugin sees it.

---

Usage

Write enums exactly as you normally would — just make sure they are exported:

// fruit.ts
export enum Fruit {
  Apple,
  Kiwi,
  Banana,
}

Import and use them identically to before:

import { Fruit } from "./fruit";

function isBanana(f: Fruit): boolean {
  return f === Fruit.Banana;
}

Multiple enums in one file work fine:

export enum Color {
  Red,
  Green,
  Blue,
}
export enum Size {
  Small,
  Medium,
  Large,
}

Non-exported enums are left completely untouched.

---

Values

Members start at 1 and auto-increment:

export enum Direction {
  North, // 1
  East, // 2
  South, // 3
  West, // 4
}

Explicit numeric initializers are supported, and auto-increment resumes from there:

export enum Status {
  Ok = 200,
  Created, // 201
  BadRequest = 400,
  NotFound, // 401
}

Negative initializers work too:

export enum Offset {
  Before = -1,
  Zero, // 0
  After, // 1
}

String initializers are supported for completeness, though the primary use case is numeric enums:

export enum Role {
  Admin = "admin",
  User = "user",
}

---

Limitations

• No reverse lookups. Fruit[1] to get "Apple" is not supported — and intentionally so. That's the string-name bloat this plugin exists to eliminate.
• No computed initializers. Expressions like Foo = Bar + 1 or Foo = someConst (referencing an import) are not evaluated; the member will be undefined at runtime. Stick to literals.
• Exported enums only. Non-exported enums are ignored and passed through to esbuild unchanged (they will compile to the standard IIFE form).
• Ambient enums. declare enum statements are ignored entirely, which is correct — they have no runtime representation.

---

License

MIT