JAVASCRIPT

How to Delete Comment from Post on Node, express and Mongoose and Ajax

// How to Delete Comment from Post on Node, express and Mongoose and Ajax

You need to know both the postId and the commentId to be able to delete the comment from posts collection. Also it would be good to delete the comment inside the comments collection.

So change your delete route to include postId and commentId as req.params. You can delete a comment from posts using the findByIdAndUpdate method and $pull operator.

router.delete("/comments/:postId/:commentId", async function (req, res) {
  try {
    const post = await Post.findByIdAndUpdate(
      req.params.postId,
      {
        $pull: { comments: req.params.commentId },
      },
      { new: true }
    );

    if (!post) {
      return res.status(400).send("Post not found");
    }

    await Comment.findByIdAndDelete(req.params.commentId);

    res.send("Success");
  } catch (err) {
    console.log(err);
    res.status(500).send("Something went wrong");
  }
});
TEST

Let's say we have this post document with 3 comments.

Posts:

{
    "_id" : ObjectId("5e8b10c49ae619486094ed10"),
    "comments" : [
        ObjectId("5e8b104f9ae619486094ed0d"),
        ObjectId("5e8b10599ae619486094ed0e"),
        ObjectId("5e8b105e9ae619486094ed0f")
    ],
    "title" : "Title",
    "description" : "Description...",
    "from" : "From",
    "postImage" : "Post Image",
    "createdAt" : ISODate("2020-04-06T14:21:40.884+03:00")
}
Comments:

{
    "_id" : ObjectId("5e8b105e9ae619486094ed0f"),
    "message" : "Comment 3"
},

{
    "_id" : ObjectId("5e8b10599ae619486094ed0e"),
    "message" : "Comment 2"
},
{
    "_id" : ObjectId("5e8b104f9ae619486094ed0d"),
    "message" : "Comment 1"
}
If we want to delete the comment with _id:5e8b10599ae619486094ed0e, we need to send a DELETE request to our route using url like this:

http://localhost:3000/posts/comments/5e8b10c49ae619486094ed10/5e8b10599ae619486094ed0e
5e8b10c49ae619486094ed10 is the postId, 5e8b10599ae619486094ed0e is the commentId.

Result will be like this:

Posts:

{
    "_id" : ObjectId("5e8b10c49ae619486094ed10"),
    "comments" : [
        ObjectId("5e8b104f9ae619486094ed0d"),
        ObjectId("5e8b105e9ae619486094ed0f")
    ],
    "title" : "Title",
    "description" : "Description...",
    "from" : "From",
    "postImage" : "Post Image",
    "createdAt" : ISODate("2020-04-06T14:21:40.884+03:00")
}
Comments:

{
    "_id" : ObjectId("5e8b105e9ae619486094ed0f"),
    "message" : "Comment 3"
},
{
    "_id" : ObjectId("5e8b104f9ae619486094ed0d"),
    "message" : "Comment 1"
}
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answered Apr 6 '20 at 11:37

SuleymanSah
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@SuleymanSahThank you so much for taking your time to explain to me how it works, i really appreciate it. I did exactly what you said with the code you gave me above, and changed my link to include post id like this ` <a class="delete-comment" href="#" data-id="<%=post.id%>/<%=item._id%>">Delete</a> ` and everything is – Chukwuma Kingsley Apr 6 '20 at 11:58