Mongoose and Node error: cannot read property 'forEach' of undefined

Question

I want to display all from my MongoDB into a table from my .ejs file. But I always get the error i wrote in my title..

Here is some code snippet:

this is my routing js file (users.js)

router.get ('/Benutzerverwaltung_Mitarbeiter', async (req, res) => {

    User.find(function (err, users) {

        // if there is an error retrieving, send the error.
        // nothing after res.send(err) will execute
        if (err)
            return res.send(err);
        res.json(users);
        res.render('Benutzerverwaltung_Mitarbeiter',{
            users: res.user
        });
    });
});

and this my .ejs file:

 <%- include('../routes/users.js'); %>
            <div>
                <table id="tabelle" class="cell-border"  class="table table-striped" cellspacing="0" class="table table-hover">
                    <thead>
                    <tr>
                        <th>UserID</th>
                        <th>Rolle</th>
                    </tr>
                    </thead>
                    <tbody>
                    <tr>
                    <% users.forEach (function (user) { %>
                    <td><%user.username%></td>
                    </tr>
                    <td><%user.admin%></td>
                    <%});%>
                    </tbody>
                </table>
                </div>

I hope you can help me out :) Cheeres, Mert

Answer 1

Both res.json and res.render are "terminal" methods - you should really only use them once when you are "finished", never both in the same method.

I think in this case you are trying to return html, not json, so you want res.render . Try this modification:

User.find(function (err, users) {

    // if there is an error retrieving, send the error.
    // nothing after res.send(err) will execute
    if (err)
        return res.send(err);
    res.render('Benutzerverwaltung_Mitarbeiter',{
        users: users || []
    });
});

Answer 2

In users.js, inside the res.render callback, I spot a typo when you assign the users property.

Array prototype functions will always throw that error above if the variable that's supposed to hold the array is not defined.