Ensures required environment variables exist, failing fast at startup if they are missing.

• ✅ Fail Fast: Throws clear errors if required environment variables are missing.
• ✅ Type Safe: Returns a typed object with your environment variables.
• ✅ Defaults: Supports default values for optional variables.
• ✅ Zero Dependencies: Lightweight and fast.
• ✅ Dual Support: Works with both ES Modules (ESM) and CommonJS (CJS).

npm install env-required

Require specific environment variables. If any are missing from process.env, requireEnv throws an error.

import { requireEnv } from 'env-required';

try {
  const { DB_URL, JWT_SECRET } = requireEnv([
    'DB_URL',
    'JWT_SECRET',
  ]);
  
  console.log('Connected to:', DB_URL);
} catch (error) {
  // Error: Missing required environment variables: DB_URL, JWT_SECRET
  console.error(error.message);
  process.exit(1);
}

You can provide a second argument with default values. If an environment variable is missing but has a default, it will use the default instead of throwing.

import { requireEnv } from 'env-required';

const { PORT, NODE_ENV } = requireEnv(
  ['NODE_ENV'], // Required
  { PORT: '3000' } // Optional with default
);

// If PORT is not in env, it validates successfully and returns '3000'
console.log(`Server running on port ${PORT} in ${NODE_ENV} mode`);

const { requireEnv } = require('env-required');

const { API_KEY } = requireEnv(['API_KEY']);

• required: Array of strings representing required environment variable names.
• defaults: (Optional) Object mapping variable names to default values.
• Returns: An object containing all requested variables (from env or defaults).
• Throws: Error if any variable in required is missing from process.env.

MIT

Author: Ahmer Arain