Using ExpressJS middleware in Socket.IO

Socket.IO namespace middleware works pretty similar to how ExpressJS middleware does. In fact, the Socket Object also contains a request and a response object that we can use to store other properties in the same manner as we do with ExpressJS middleware functions:

namespace.use((socket, next) => { 
    const req = socket.request 
    const res = socket.request.res 
    next() 
}) 

Because ExpressJS middleware functions have the following signature:

const expressMiddleware = (request, response, next) => { 
    next() 
} 

We can safely execute the same function in a Socket.IO namespace middleware passing the necessary arguments:

root.use((socket, next) => { 
    const req = socket.request 
    const res = socket.request.res 
    expressMiddleware(req, res, next) 
}) 

However, that doesn't mean that all ExpressJS middleware functions...