unused-env-checker

A CLI tool for Node.js projects that scans your codebase and compares used environment variables against your .env file.

Installation

npm install -g unused-env-checker

Or run instantly without installing:

npx unused-env-checker

Usage

Navigate to your project root (where .env lives) and run:

npx unused-env-checker

Output

🔍 Scanning project...

  ✅ PORT is used
  ✅ JWT_SECRET is used

  ⚠ UNUSED VARIABLES:
    - OLD_API_KEY
    - TEMP_SECRET

  ❌ MISSING VARIABLES:
    - DATABASE_URL

The tool exits with:

• 0 — all env vars are in use, no missing variables
• 1 — missing variables detected (used in code but missing from .env)

Features

• Scans .js, .ts, .jsx, .tsx files recursively
• Automatically ignores node_modules, dist, build, .git
• Detects used, unused, and missing environment variables
• Color-coded terminal output (green/yellow/red)
• Protects against dangerous keys (__proto__, constructor, etc.)
• Zero external dependencies

What It Checks

| Status | Meaning | |--------|---------| | ✅ Used | Found in .env and referenced in code | | ⚠ Unused | In .env but never used in code | | ❌ Missing | Used in code but missing from .env |

Test Examples

// Test 1: Basic scan with .env present
// Tests used, unused, and missing variable detection

// Test 2: Missing variables detection
// Ensures code-used vars not in .env are flagged

// Test 3: Ignores node_modules
// Variables only used in node_modules show as unused

// Test 4: No .env file
// Gracefully handles missing .env files

// Test 5: Dangerous keys ignored
// __proto__ and constructor are filtered out

// Test 6: Extension scan
// Scans .ts and .tsx files in addition to .js/.jsx

Run tests:

node test.js

Why?

Tired of bloated .env files with stale variables? Or debugging missing environment variables in production? This tool helps you keep your environment configuration clean and complete.

License

MIT