env-typegen-typescript-types-from-env

Env Typegen

Generate TypeScript types from your .env file. Smart type inference for numbers, booleans, URLs.

Installation

npm install -g @lxgicstudios/env-typegen

Commands

Generate Types

npx @lxgicstudios/env-typegen
npx @lxgicstudios/env-typegen .env.local
npx @lxgicstudios/env-typegen -o src/types/env.d.ts

With Zod Schema

npx @lxgicstudios/env-typegen --zod

Example

Input .env:

# Database
DATABASE_URL=postgresql://localhost:5432/db
DB_POOL_SIZE=10

# Server
PORT=3000
DEBUG=true

# API
API_KEY=sk_live_abc123

Output:

export interface Env {
  /** Database */
  DATABASE_URL: string;
  DB_POOL_SIZE: number;
  /** Server */
  PORT: number;
  DEBUG: boolean;
  /** API */
  API_KEY: string;
}

export function getEnv(): Env {
  return {
    DATABASE_URL: process.env.DATABASE_URL || '',
    DB_POOL_SIZE: Number(process.env.DB_POOL_SIZE),
    PORT: Number(process.env.PORT),
    DEBUG: ['true', '1', 'yes'].includes(process.env.DEBUG?.toLowerCase() || ''),
    API_KEY: process.env.API_KEY || '',
  };
}

declare global {
  namespace NodeJS {
    interface ProcessEnv {
      DATABASE_URL: string;
      DB_POOL_SIZE: string;
      PORT: string;
      DEBUG: string;
      API_KEY: string;
    }
  }
}

Type Inference

Pattern	Type
PORT=3000	number
DEBUG=true	boolean
API_URL=https://...	string (URL)
[email protected]	string (email)
Everything else	string

Options

Option	Description
-i, --input	Input file (default: .env)
-o, --output	Output file (default: env.d.ts)
--zod	Generate Zod schema too
--name	Interface name (default: Env)

Common Use Cases

Generate for project:

npx @lxgicstudios/env-typegen -o src/types/env.d.ts

With runtime validation:

npx @lxgicstudios/env-typegen --zod -o src/env.ts

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