How to check wether the user is logged in with Firebase on the Client Side?

Question

EDIT:

Thank you for your help ! You helped me pinpoint the problem and showed me the solution I was looking for: Accessing Express.js local variables in client side JavaScript

CODE:

index.ejs

$('.UpvoteButton').click(function () {
    if (authdata == null) {
        return res.redirect('/users/login');
    }
    else {
        var $this = $(this);
        var $other = $('.DownvoteButton');
        if ($this.hasClass("on")) {
            $this.removeClass("on");
        } else if (!$this.hasClass('on') && $other.hasClass("on")) {
            $this.addClass('on');
            $other.removeClass("on");
        } else {
            $this.addClass('on');
        } 
    } 
});

app.js

//Global vars
app.use(function(req, res, next) {
    res.locals.authdata = firebase.auth().currentUser;
    next();
});

PROBLEM:

When I click, nothing happens. It worked before when I didn't have the if-else statement and the redirect statement.

N.B.: This is inside an EJS file. I am using Node.js.

QUESTION:

What have I done wrong ?

It's **never** going to work that way, you can't do `res.redirect` on the clientside — adeneo, Oct 24 '16 at 14:22
@adeneo I also tried: `window.location.href = "/users/login";` — Coder1000, Oct 24 '16 at 14:23
That should work, assuming `authdata` is defined, and your condition works — adeneo, Oct 24 '16 at 14:24
@Coder1000 forget about your serverside stuff in node, we need a [mcve] demonstrating the problem. — Jamiec, Oct 24 '16 at 14:24
My suspicion is that `authdata` is a server-side variable. Let's find out... /popcorn — canon, Oct 24 '16 at 14:26
@LucasCosta That's another problem I have, log statements don't work :/ — Coder1000, Oct 24 '16 at 14:27
As @Jamiec said, the example provided is difficult to test and debug; please post what the value of `authdata` is. Can you also replace `authdata == null` with `false` to test whether the `else` statement runs? — Quangdao Nguyen, Oct 24 '16 at 14:27
you can't access directly server-side variable in the front-end in JQuery — BrTkCa, Oct 24 '16 at 14:29
@LucasCosta Yes, that was the issue. Hmmm. But I need to check wether the user is logged in. Hmmm.... — Coder1000, Oct 24 '16 at 14:32
http://stackoverflow.com/questions/10919650/accessing-express-js-local-variables-in-client-side-javascript — Jamiec, Oct 24 '16 at 14:33

score 1 · Accepted Answer · edited May 23 '17 at 12:06

As stated, you're trying to access a server-sided variable on the client side. Check this out: Accessing EJS variable in Javascript logic.

Essentially, you'll want to declare the variable on the client side using:

<script>
    var authdata = <%= authdata %>            
</script>

Then, you can add your code. Remember to change the redirect to something that is recognized by the client ie. window.location.href = "/users/login";

How to check wether the user is logged in with Firebase on the Client Side?

1 Answers1