I am using '*' for catch the error 404 in Express.js

How could I know the path name of the error url?

app.get('*',  (req, res) => {
    console.log("route: " + JSON.stringify(req.route));
});

req.route returns an anonymous name.

route: {
    "path": "*",
    "stack":[{
        "name": "anonymous",
        "keys": [],
        "regexp": {
            "fast_star": false,
            "fast_slash": false
        },
        "method": "get"
    }],
    "methods": {
        "get":true
    }
}