Middleware to redirect trailing slash with query parameters

redirect.js

const url = require('url')

module.exports = (config) => {

    return (req, res, next) => {
        let current = req.protocol + '//' + req.get('host') + req.originalUrl,
            withSlash = addSlash(current)
        
        if (current == withSlash) {
            next()
        } else {
            res.redirect(withSlash)
        }
    }

    function addSlash(original) {
        let parsedUrl = url.parse(original)
        if (parsedUrl.pathname.slice(-1) === '/') {
            return original
        } else {
            return original.replace(parsedUrl.pathname, parsedUrl.pathname + '/')
        }
    }
}