Middleware for Next.js API Routes

Next.js released version 9, which added API Routes. This enabled us to write APIs. Currently, Next.js release version 10, but, I think... still, something was missing: Middleware. Because the official Next.js docs recommend writing functions inside your API route handler, there is no easy way to implement it.

So, I write use-next-middleware. It's very clean, minimal and composable middleware patterns.

Installation

Use the package manager yarn or npm to install use-next-middleware.

yarn add use-next-middleware

Quick Start

import { useNextMiddleware } from 'next-api-middleware'
import { NextApiRequest } from 'next'

const handler = async (req, res) => {
  const { name } = req.user
  const { role } = req.permissions

  res.status(200)
  res.send(`Hello, ${name}, Role is ${role}`)
}

export default useNextMiddleware(
  async (req: NextApiRequest & { user: { name: string } }, res, next) => {
    console.log('Add user.name in request')
    req.user = {
      name: 'Snoop',
    }

    next()
  },

  async (
    req: NextApiRequest & { permissions: { role: string } },
    res,
    next
  ) => {
    console.log('Add permissions.role in request')

    req.permissions = {
      role: 'admin',
    }

    await next()
  }
)(handler)

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

Please make sure to update tests as appropriate.

License

MIT