How do I insert an element into an existing document? - node.js

Question

I have an existing document that contains a nested array of elements (I'm not exactly sure of the terminology here). I have no problem creating the document. The problem arises when I need to insert a new element into the existing document. The code below may clarify what I'm trying to do:
Controller:
var Post = require('./models/post');
app.post('/post/:id/comment', function(req, res) {
var updateData = {
comments.comment: req.body.comment
comments.name: req.body.name,
};
Post.update({_id: req.params.id},updateData, function(err,affected) {
console.log('affected rows %d', affected);
});
});
Model:
var mongoose = require('mongoose');
var postSchema = mongoose.Schema({
post : String,
name : String,
created : {
type: Date,
default: Date.now
},
comments : [{
comment : String,
name : String,
created : {
type: Date,
default: Date.now
}
}]
});
module.exports = mongoose.model('Posts', postSchema);
So, each post can contain multiple comments. I'm just not sure how to insert a new comment into an existing post.

Answer 1

Since comments is declared as array, try to use
Post.update({_id:yourid}, { $push : { comments: { comment: '', name: '' } } }, ...

Answer 2

You can convert the object returned from mongodb in to an js object, and push new comment into the comments array. See the following:
var postSchema = require('./postSchema'); // your postSchema model file
postSchema.findOne({name: 'name-of-the-post'}, function (err, doc) { //find the post base on post name or whatever criteria
if (err)
console.log(err);
else {
if (!doc) { //if not found, create new post and insert into db
var obj = new postSchema({
post: '...'
name: '...'
...
});
obj.save(function (err) {
if (err)
console.log(err);
});
} else {
// if found, convert the post into an object, delete the _id field, and add new comment to this post
var obj = doc.toObject();
delete obj._id;
obj.comments.push(req.body.comment); // push new comment to comments array
postSchema.update(
{
'_id': doc._id
}, obj, {upsert: true}, function (err) { // upsert: true
if (err)
console.log(err);
});
}
console.log('Done');
}
});