Adding comment features to blog using express and handlebars - node.js

Question

I'm trying to create a blog site that has the ability to comment on a blog/article. I have the end point
app.get('/post/:slug', function(req, res) {
var _slug = req.params.slug;
var blog_post = _.findWhere(_DATA, { slug: _slug });
if (!blog_post) return res.render('404');
res.render('post', blog_post);
});
that handles the display of a blog/article using HandleBars. It retrieves a post from database _DATA and simply display it using the template post.handlebars. It right now does nothing else.
I would like to add the ability to comment on this article. I'm very new to web programming and don't know how to handle requests like that. Right now, my idea is to add
<article>
<form method="POST" action="/comment">
<div class="input-field">
<label>Comment:</label>
<textarea type="text" name="comment" rows="20" placeholder="What's on your mind?"></textarea>
</div>
<button type="submit">Add Comment</button>
</form>
</article>
to the bottom of my post.handlebars and add the end point app.post('/comment', function(req, res) {});
But this presents multiple problems, namely, how would I know which article I'm commenting on? In this new end-point, my req.body would contain nothing except the contents of the comment.
What is the proper way to handle this?

Answer 1

Put the ID of your article in the comment form as an hidden input. When you'll submit the form you'll get the article-id value.
I've used handlebar to place the article id in the form change the value of article.id according to your data.
<article>
<form method="POST" action="/comment">
<div class="input-field">
<label>Comment:</label>
<textarea type="text" name="comment" rows="20" placeholder="What's on your mind?"></textarea>
</div>
<input type="hidden" name="article-id" value="{{article.id}}">
<button type="submit">Add Comment</button>
</form>
</article>