Express 3 error middleware not being called

Question

I am trying to setup error handling for my express app and running into the following problem.

I defined an error middleware and add it as the last middleware:

Answer 1

instead of making

app.get('/datenschutz', function(req, res, next){
        return next(new Error('Just testing')); // handle everything here
    });

you can install express-async-errors

and just make

app.get('/datenschutz', function(req, res){
       throw new Error('Just testing');
    });

it works as expected