MongoDB middleware that exposes a DB object to Express.js req.param. https://github.com/floatdrop/express-mongo-db

mongoMiddleware.js

const connection = require('mongodb').MongoClient.connect('mongoServer')
const mongoMiddleware = (req, res, next) => {
  connection
    .then(db => {
      req['db'] = db.collection('documents')
      next()
    })
    .catch(err => next(err))
}

app.use(mongoMiddleware)

app.get('/', (req, res) => {
  req.db.find().toArray()
    .then(docs => res.send(docs))
    .catch(err => {
      throw err
    })
})

const ObjectID = require('mongodb').ObjectID
app.get('/:id', (req, res) => {
  req.db.findOne({ _id: ObjectID(req.params.id) })
  .then(doc => res.send(doc))
  .catch(err => {
    throw err
  })
})