Question

I have embedded comments in a posts model. I am using mongoosejs. After pushing a new comment in a post, I want to access the id of the newly added embedded comment. Not sure how to get it.

Here is how the code looks like.

var post = Post.findById(postId,function(err,post){

   if(err){console.log(err);self.res.send(500,err)}

   post.comments.push(comment);

   post.save(function(err,story){
       if(err){console.log(err);self.res.send(500,err)}
           self.res.send(comment);
   })


});

In the above code, the id of the comment is not returned. Note there is a _id field which is created in the db.

The schema looks like

var CommentSchema = new Schema({
  ...
})

var PostSchema = new Schema({
    ...
    comments:[CommentSchema],
    ...
});

Answer 1

A document’s _id value is actually assigned by the client, not the server. So the _id of the new comment is available right after you call:

post.comments.push(comment);

The embedded doc pushed to post.comments will have its _id assigned as it’s added, so you can pull it from there:

console.log('_id assigned is: %s', post.comments[post.comments.length-1]._id);