TypeSpec Enum Emitter

A custom TypeSpec emitter that exports enums as JavaScript const objects with proper TypeScript type definitions.

Features

• Converts TypeSpec enums to JavaScript const objects
• Generates TypeScript declaration files (.d.ts)
• Supports string and numeric enum values
• Uses the TypeSpec emitter framework

Installation

npm install typespec-enum-emitter

Usage

1. Create a TypeSpec file with enums

import "typespec-enum-emitter";

enum Status {
	Active,
	Inactive,
	Pending,
}

enum Priority {
	Low: "low",
	Medium: "medium",
	High: "high",
}

enum HttpStatusCode {
	OK: 200,
	NotFound: 404,
	InternalServerError: 500,
}

2. Configure tspconfig.yaml

emit:
  - @kattebak/typespec-enum-emitter
options:
  typespec-enum-emitter:
    output-file: "enums.js"
    emitter-output-dir: "{cwd}/build/ts-enums"
    package-name: "@mycorp/enums"
    package-version: "1.0.0"

3. Compile

npx tsp compile .

4. Generated Output

enums.js:

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });

export const Status = {
  Active: "Active",
  Inactive: "Inactive",
  Pending: "Pending",
};

export const Priority = {
  Low: "low",
  Medium: "medium",
  High: "high",
};

export const HttpStatusCode = {
  OK: 200,
  NotFound: 404,
  InternalServerError: 500,
};

enums.d.ts:

export declare const Status: {
  readonly Active: "Active";
  readonly Inactive: "Inactive";
  readonly Pending: "Pending";
};

export declare const Priority: {
  readonly Low: "low";
  readonly Medium: "medium";
  readonly High: "high";
};

export declare const HttpStatusCode: {
  readonly OK: 200;
  readonly NotFound: 404;
  readonly InternalServerError: 500;
};

Configuration Options

• output-file: Name of the output file (default: "enums.js")
• emitter-output-dir: Custom output directory (supports variable interpolation like {cwd}, {project-root})
• package-name: If provided, generates a package.json file with this name
• package-version: Version for the generated package.json (default: "0.0.1")

Why Use This?

TypeScript enums have some quirks:

• They generate runtime code that can be hard to tree-shake
• Const enums don't preserve values at runtime
• Regular enums can have unexpected behavior with numeric values

This emitter generates simple const objects that:

• Are fully tree-shakeable
• Have clear runtime behavior
• Work seamlessly with TypeScript's type system
• Are easy to inspect and debug

Implementation

Built using the TypeSpec emitter framework with:

• @typespec/compiler for AST traversal
• Namespace-aware enum collection
• Proper TypeScript declaration generation