📄 getEnv

A lightweight utility for retrieving environment variables in Deno, supporting both local .env files (for development) and system environment variables (for production).

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✨ Features

✅ Loads .env variables using deno_std/dotenv ✅ Falls back to Deno.env.get() for system environment ✅ Supports default fallback values ✅ Safe to use even if .env is missing (no crashes) ✅ Designed for Deno projects

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📦 Installation

import getEnv from './get-env.ts';

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🔧 How it works

• Priority order: 1️⃣ .env file (loaded at startup, dev mode) 2️⃣ Deno.env.get() (system environment, prod mode) 3️⃣ Supplied default value (if provided) 4️⃣ undefined (if not found anywhere)

• Uses the Deno standard library’s dotenv module to parse .env.

• Automatically ignores MissingEnvVarsError if no .env file exists.

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🚀 Usage

const port = getEnv('PORT', '3000');
console.log(`Server running on port ${port}`);

Without default:

const token = getEnv('API_TOKEN');
if (!token) throw new Error('Missing API_TOKEN!');

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🔍 Example

Given a .env file:

PORT=8080
MODE=development

Code:

const port = getEnv('PORT', '3000');  // ➔ '8080'
const mode = getEnv('MODE');          // ➔ 'development'
const missing = getEnv('UNKNOWN', 'default');  // ➔ 'default'

In production (without .env), it checks system environment:

$ DENO_ENV=production deno run app.ts

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⚠️ Notes

• Only string values are supported.
• undefined is returned if the key is missing and no default is provided.
• This module does not mutate Deno.env — it only reads.
• For secure environments, avoid hardcoding sensitive values.

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Bien sûr ! Voici un exemple plus simple et clair d’utilisation avancée avec l’opérateur diamant (<T>) :

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💎 Advanced Example with Type Parameter

import getEnv from './get-env.ts';

// Define allowed keys using a union type
type MyEnvKeys = 'APP_NAME' | 'APP_PORT' | 'ENV';

// Use the diamond operator <MyEnvKeys> to hint TypeScript
const appName = getEnv<MyEnvKeys>('APP_NAME', 'DefaultApp');
const port = getEnv<MyEnvKeys>('APP_PORT', '8000');
const environment = getEnv<MyEnvKeys>('ENV', 'development');

console.log(`🚀 ${appName} | Port: ${port} | Mode: ${environment}`);

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What this does

✅ Type safety → You can’t accidentally pass a wrong key. ✅ Better autocomplete → Your editor will suggest only 'APP_NAME', 'APP_PORT', or 'ENV'. ✅ Clean fallback → Defaults are still supported.

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Example Output

If .env contains:

APP_NAME=MyAdvancedApp
APP_PORT=4000
ENV=production

You’ll get:

🚀 MyAdvancedApp | Port: 4000 | Mode: production

If some keys are missing:

🚀 DefaultApp | Port: 8000 | Mode: development

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Why use <MyEnvKeys>?

✅ Helps document which environment variables your app uses. ✅ Reduces typos and runtime errors. ✅ Makes your code self-explanatory.