Condition not returning errors (Express.js) – Blancer.com Tutorials and projects

When I call a GET request in Postman with the url “localhost:3000/api/users/id/” without the number of the ID, I’d like to have a return like this one when I call a GET request with the query empty:

{
    "errors": [
        {
            "type": "field",
            "msg": "Must not be empty",
            "path": "filter",
            "location": "body"
        }
}

but insteaded this is the return I have:

<html lang="en">

<head>
    <meta charset="utf-8">
    <title>Error</title>
</head>

<body>
    <pre>Cannot GET /api/users/id/</pre>
</body>

this the code:

app.get("/api/users/id/:id", findUserIndex, checkSchema(getUserValidationIdSchema), (req, res) => {

    const result = validationResult(req);
    const {userIndex} = req;

    if (!result.isEmpty()) return res.status(400).send({errors: result.array()});

    if (result.isEmpty()) return res.send(users[userIndex]);

})

this is the function finderUserIndex:

const findUserIndex = (req, res, next) => {

    const {params: {id}} = req;
    const parsedId = parseInt(id);

    if (isNaN(parsedId)) return res.sendStatus(400);

    const userIndex = users.findIndex((user) => user.id === parsedId);

    if (userIndex === -1) return res.sendStatus(404);

    req.userIndex = userIndex;
    req.parsedId = parsedId;

    next();

}

and this is the schema get getUserValidationIdSchema:

export const getUserValidationIdSchema = {
    id: {
        notEmpty: {errorMessage: "Must not be empty"},
    }
}