Node.js how to exit an application?

Question

Node.js

I have an endpoint. And two callbacks below.

router.put('/fixtures/change/main/:fixtoId', jwtTokenUserRole,ChangeMainFixture )

exports.jwtTokenUserRole = async (req, res,next) =>{
    
    let head = req.headers

    var token = head.authorization.replace('Bearer ','')
   
    let j = jwt.decode(token)

    req.auth = j.role
    
    next()
}

exports.ChangeMainFixture = (req,res) =>{
    let fixMain = req.fixtur
   
    fixMain = _.extend(fixMain, req.body)
    fixMain.save((err, result) => {
        
        if (err) {
            return res.status(400).json({
                error: err
            })
        }
        
        res.json(result)
    })
}

I want the first callback to define the user's permissions. And if the request was not made by the admin. That did not go further along the calbeks. I found the process.exit(1); function in the documentation. But the Nodejs developers do not recommend using this. Keeping track of rights in the last callback and giving response from there is not an option. I can set it up with a thousand if(), but I would like to find a better solution.

Answer 1

There is such a thing as middleware, an intermediary that will cut off for the necessary routes according to the desired condition (which is the admin). Write once and add it to the routes, while the elbow - to the route it will come if other layers are skipped.
https://expressjs.com/en/guide/using-middleware.html