@lxgicstudios/env-typegen

Generate TypeScript types from your .env files with smart type inference.

No more process.env.PORT as unknown as number. Get proper types automatically.

Installation

# Use directly with npx (recommended)
npx @lxgicstudios/env-typegen

# Or install globally
npm install -g @lxgicstudios/env-typegen

Usage

# Generate types from .env in current directory
npx @lxgicstudios/env-typegen

# Generate from specific file
npx @lxgicstudios/env-typegen .env.local

# Output to custom path
npx @lxgicstudios/env-typegen -o src/types/env.d.ts

# Also generate Zod schema for runtime validation
npx @lxgicstudios/env-typegen --zod

Example

Given this .env:

# Database configuration
DATABASE_URL=postgresql://localhost:5432/mydb
DB_POOL_SIZE=10

# Server settings
PORT=3000
DEBUG=true

# External services
API_KEY=sk_live_abc123
[email protected]

Running npx @lxgicstudios/env-typegen generates:

export interface Env {
  /** Database configuration */
  DATABASE_URL: string;
  DB_POOL_SIZE: number;
  /** Server settings */
  PORT: number;
  DEBUG: boolean;
  /** External services */
  API_KEY: string;
  ADMIN_EMAIL: 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 || '',
    ADMIN_EMAIL: process.env.ADMIN_EMAIL || '',
  } as Env;
}

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

Type Inference

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

Options

| Option | Description | |--------|-------------| | -i, --input <file> | Input .env file (default: .env) | | -o, --output <file> | Output file (default: env.d.ts) | | --zod | Also generate Zod schema | | --name <name> | Interface name (default: Env) | | -h, --help | Show help |

Programmatic API

import { 
  parseEnvFile, 
  generateTypeScript, 
  generateZodSchema 
} from '@lxgicstudios/env-typegen';

// Parse .env file
const variables = parseEnvFile('.env');

// Generate TypeScript
const ts = generateTypeScript(variables, 'MyEnv');

// Generate Zod schema
const zod = generateZodSchema(variables);

Built by LXGIC Studios

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