🛡️ Introducing envguard – Zero-Boilerplate Environment Variable Validation for Node.js

#showdev #npm #productivity #javascript

Hey devs! 👋

I just published my latest npm package @rohansm14/envguard and wanted to share it with the community.

The Problem

We've all been there – your app crashes at 2 AM because someone forgot to set DATABASE_URL in production, or DEBUG=false gets treated as a string instead of a boolean. Environment variable bugs are frustrating, hard to debug, and completely preventable.

The Solution

envguard validates all your environment variables at startup with a single function call. No more if (!process.env.X) throw... scattered everywhere. Just define your schema once and you're good to go.

Quick Example

import 'dotenv/config'
import { guard } from '@rohansm14/envguard'

const env = guard({
  PORT:         { type: 'number',  default: 3000 },
  DATABASE_URL: { type: 'string',  required: true },
  DEBUG:        { type: 'boolean', default: false },
  JWT_SECRET:   { type: 'string',  required: true, minLength: 32 }
})

// env.PORT is 3000 (number, not string!)
// env.DEBUG is false (boolean, not string!)
app.listen(env.PORT)
mongoose.connect(env.DATABASE_URL)

Key Features

✅ Type coercion – "3000" → 3000, "true" → true
✅ Required field validation – throws clear errors for missing vars
✅ Default values – fallback when vars aren't set
✅ String length validation – ensure your secrets are actually secret-worthy
✅ All errors at once – see everything that's wrong, not just the first issue
✅ Zero dependencies – lightweight and simple

Beautiful Error Messages

Instead of cryptic undefined errors buried deep in your app:

[envguard] Missing or invalid environment variables:
  ✗ DATABASE_URL → required but not set
  ✗ JWT_SECRET   → must be at least 32 characters (got 8)
  ✗ PORT         → expected number, got "abc"

Fix these before starting the server.

Schema Options

Option	Type	Description
`type`	`'string'` \	`'number'` \
`required`	`boolean`	Throws if not set
`default`	any	Fallback value
`minLength`	`number`	Min string length (great for secrets!)

Installation

npm install @rohansm14/envguard

Test Coverage

The package comes with comprehensive tests covering:

Required field validation
Default values
Type coercion (numbers, booleans, strings)
Minimum length constraints
Multiple error aggregation
Edge cases (empty schemas, extra env vars)

npm test

Pro Tips

Call it early – Put guard() at the very top of your entry file, before any other imports
Use with dotenv – envguard doesn't load .env files, so pair it with dotenv
Fail fast – envguard throws on startup, so you catch issues before they cause weird runtime behavior
Type safety – Combine with TypeScript or JSDoc for even better DX

What's Next?

I'm planning to add:

Custom validators (regex patterns, enums, etc.)
TypeScript definitions
Async secret loading (AWS Secrets Manager, Vault, etc.)

Feedback Welcome!

This is v1.0.0 and I'd love to hear your thoughts! Drop a comment, open an issue, or shoot me a PR. What features would make this more useful for your workflow?