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Express Middleware Compatibility

Vegaa maintains its minimalist DNA while allowing you to use existing Express middleware seamlessly.

Why Express Compatibility?​

You might have existing Express middleware you want to use, or prefer certain Express packages. Vegaa lets you use them without compromising its clean, context-based API.

Enabling Express Compatibility​

import { vegaa, enableExpressCompat } from 'vegaa'

// Enable Express compatibility
enableExpressCompat(vegaa)

// Now you can use Express middleware
vegaa.useExpressMiddleware(helmet())

Using Express Middleware​

Global Middleware​

import { vegaa, enableExpressCompat } from 'vegaa'
import helmet from 'helmet'
import cors from 'cors'

enableExpressCompat(vegaa)

// Use Express middleware globally
vegaa.useExpressMiddleware(helmet())
vegaa.useExpressMiddleware(cors())

Path-Specific Middleware​

// Apply middleware to specific paths
vegaa.useExpressMiddleware('/api', (req, res, next) => {
  req.apiVersion = 'v1'
  next()
})

Custom Express Middleware​

// Simple logging middleware
vegaa.useExpressMiddleware((req, res, next) => {
  console.log(`${req.method} ${req.url}`)
  next()
})

// Async middleware
vegaa.useExpressMiddleware(async (req, res, next) => {
  await someAsyncOperation()
  next()
})

Accessing Express Request Properties​

Express middleware can set properties on req, which become available in Vegaa routes:

vegaa.useExpressMiddleware((req, res, next) => {
  req.user = { id: 1, name: 'John' }
  next()
})

// Access in Vegaa route
route('/profile').get((user) => {
  return { user }  // user comes from req.user
})

Error Handling​

Express error middleware integrates with Vegaa's error handling:

vegaa.useExpressMiddleware((err, req, res, next) => {
  console.error('Error:', err)
  res.status(500).json({ error: 'Internal Server Error' })
})

Examples​

Using Helmet for Security​

import { vegaa, enableExpressCompat, route } from 'vegaa'
import helmet from 'helmet'

enableExpressCompat(vegaa)
vegaa.useExpressMiddleware(helmet())

route('/api').get(() => ({ message: 'Secure API' }))

CORS Configuration​

import cors from 'cors'

vegaa.useExpressMiddleware(cors({
  origin: 'https://example.com'
}))

Request Logging​

vegaa.useExpressMiddleware((req, res, next) => {
  console.log(`[${new Date().toISOString()}] ${req.method} ${req.url}`)
  next()
})

Best Practices​

  1. Enable compatibility once - Call enableExpressCompat at the start of your app
  2. Keep Vegaa routes clean - Use Express middleware for cross-cutting concerns
  3. Use Vegaa middleware when possible - It's more integrated with Vegaa's context system
  4. Document middleware - Make it clear which middleware is Express-based

Next Steps​