Mongo - request all embedded comments in Post query - mongodb

Question

I'm adapting the Microscope tutorial to my needs and am having difficulty writing a query which gathers all the comments embedded within a post.
Here is my query so far:
Posts.find({"postId": this._id}, {"comments":{}});
Here is an example post I want to get the comments from:
{
"_id": "Ad9RYqWqbsJKZx3h7",
"title": "Writing decimal number words as a decimal number",
"userId": "9yqTaFeQSqvKmNn8B",
"author": "Sacha Greif",
"submitted": "2017-01-05T03:26:18.908Z",
"commentsCount": 4,
"comments": [
{
"body": "Hello",
"postId": "Ad9RYqWqbsJKZx3h7",
"userId": "73qGvsRuqNtXcaZDx",
"author": "student",
"submitted": "2017-01-05T10:26:45.745Z"
},
{
"body": "How are you?",
"postId": "Ad9RYqWqbsJKZx3h7",
"userId": "73qGvsRuqNtXcaZDx",
"author": "student",
"submitted": "2017-01-05T10:28:17.225Z"
}
]}
It seems to return a cursor, but I am not able to use the toArray() function on it.
I have read this is not possible (Filtering embedded documents in MongoDB), but this was six years ago...
I've also seen posts about $slice and aggregate but can't seem to get me head around them.
Any help much appreciated!

Answer 1

query this->
Posts.find({"comments.postId": this._id});

Answer 2

You can just simply use findOne to get the specific document from the collection and you can use forEach Loop to iterate through the comments array of that document.
var post = Posts.findOne({_id: "<id_of_the_post>"});
var post_comments = post.comments; // post_comments contains the comments array
or if you want to do something with each comment use forEach
post_comments.forEach(function(entry, index, arr){
// entry has the comment object
//do something with the comment
});
I hope this helps.