de-env

A simple and efficient environment variable parser that generates TypeScript/JavaScript files from your environment variables using a schema-based approach.

Visit our official website: de-env.v1noid.com

What it does

de-env takes your environment variables and converts them into a strongly-typed TypeScript/JavaScript module using a schema definition. It helps your project validate environment variables in two ways:

1. Manual Schema Definition: Define your environment variable types and requirements explicitly
2. Automatic Schema Generation: Use de-env <env-path> <output-path> command to automatically generate a schema from your .env file

Key Features

• Generates a schema from your environment variables
• Handles type casting (string, number, boolean)
• Supports optional fields validation using #! prefix in .env
• Supports different module formats (ESM/CommonJS)
• Automatic TypeScript type generation for better debugging

Example

Given environment variables:

# Database configuration
DB_HOST=localhost
DB_PORT=5432
DB_NAME=mydb
#!
API_KEY="your-secret-key"  # Using #! marks this as optional
DEBUG=true

You can also use optional block

# starting of optional block with #!!!
#!!!
DB_HOST=localhost
DB_PORT=5432
DB_NAME=mydb
API_KEY="your-secret-key"
DEBUG=true
#---
# use #--- to end the block

Now all the variable in between the comment are marked as optional

import { EnvSchema } from "de-env";

export const Env = EnvSchema({
  DB_HOST: ["string", "optional"],
  DB_PORT: ["number", "optional"],
  DB_NAME: ["string", "optional"],
  API_KEY: ["string", "optional"],
  DEBUG: ["string", "optional"]
});

Automatic Schema Generation

Running de-env .env config.env.ts will automatically generate:

// config.env.ts
import { EnvSchema } from "de-env";

export const Env = EnvSchema({
  DB_HOST: "string",
  DB_PORT: "number",
  DB_NAME: "string",
  API_KEY: ["string", "optional"], // Automatically marked as optional due to #!
  DEBUG: "boolean"
});

Manual Schema Definition

You can also manually define your schema:

// config.env.ts
import { EnvSchema } from "de-env";

export const Env = EnvSchema({
  DB_HOST: "string",
  DB_PORT: "number",
  DB_NAME: ["string", "optional"], // Mark as optional
  API_KEY: ["string", "optional"], // Mark as optional
  DEBUG: "boolean"
});

Now you can use your environment variables with full TypeScript support:

import Env from './config';

// TypeScript will provide autocomplete and type checking
console.log(Env("DB_HOST" /* Because of typescript
you will get the keys suggestion here */));    // Type: string
console.log(Env("DB_PORT"));    // Type: number
console.log(Env("API_KEY"));    // Type: string
console.log(Env("DEBUG"));      // Type: boolean

// Will throw an error if DB_NAME is not set in environment variables
console.log(Env("DB_NAME"));    // Type: string

Installation

npm install de-env

Usage

Automatic Schema Generation

Using cli tool to generate

de-env <env-path> <output-path>

Schema Types

The schema supports the following types:

• "string" - String values
• "number" - Numeric values (automatically converted)
• "boolean" - Boolean values (automatically converted)

You can mark fields as optional in two ways:

1. Using #! prefix in your .env file:

#!
optional_VAR=value

2. Using an array with "optional" in your schema:

{
  optional_FIELD: ["string", "optional"],
  OPTIONAL_FIELD: "string"
}

Features

• Automatic schema generation from environment variables using de-env
• Manual schema definition for fine-grained control
• Automatic type casting based on schema
• optional field validation (using #! or schema definition)
• TypeScript support with full type inference
• Automatic type generation for better debugging

Workflow

1. Set up your environment variables (use #! prefix for optional variables)
2. Run de-env config.ts to automatically generate the schema or manually write schema
3. Use the Env function in your code with full type safety

License

MIT