Handling json response in .ejs page node.js

Question

Handling json response in .ejs page node.js

I am very much beginner with node.js!

I am unable to handle json response in .ejs page. Its when user tries logging in with wrong details then I am rendering same page and sending some JSON response and checking if this sent response is not null then show some alert or something like "Unidentified details".

 res.redirect('login', { LoginInvalid: "LoginInvalid" });

Using response in page-

<script>
    if(JSON.stringify(<%-LoginInvalid%>)!=null){
    console.log('invalid details'); 
    }
</script>

But this script doesn't run and page shows me reference error with LoginInvalid is not defined

Please guid me troubleshooting this tiny issue.

javascript
jquery
json
node.js

Answer 1

You can't pass a variable to your ejs template if you are using res.redirect() (Read http://expressjs.com/api.html#res.redirect for more information). If you do want to pass some variable in it, the only way is to use GET query string like this

res.redirect('login?LoginInvalid=LoginInvalid');

And parse LoginInvalid query string from the login controller.

Answer 2

You can use flash messages with the express-flash module.

var flash = require('express-flash');

app.use(flash());

Then in your route,

req.flash('login', { LoginInvalid: "LoginInvalid" });
res.redirect('/login');

And in your view,

<% if (messages.login.LoginInvalid) { %>
    <%= messages.login.LoginInvalid
<% } %>