Mongoose: change specific element in array that matches query - node.js

Question

Schema:
var User = new Schema({
userId: String,
name: String,
lastLogin: Date,
lastPost: Date,
followers: [String],
following: [String],
posts: [{
date: Date,
title: String,
likes: Number,
public: Boolean,
comments: [{
date: Date,
comment: String,
postedBy: String
}],
modules:[{
moduleType: String,
entries: [{
file: String,
date: Date
}]
}]
}]
});
Query:
await User.updateOne({
$and:[
{ userId: id },
{ posts: { $elemMatch: { title: activityTitle }}}
]},
{ $inc: { "posts.0.likes": 1 }}
)
.exec()
.then(() => {
console.log(`Liked activity '${activityTitle}'`)
})
This query obviously only increases the likes for the first element in posts.
But what I am trying to do is increase the likes for the post that contains the title: activityTitle.
For example a user, User1, can have 3 posts with titles, post1, post2, post3. But I want to increase the likes on post3. I have no way of knowing which post to like since when I query, it returns the whole array and not just the element with the same title.

Answer 1

You're close to result. You should use dot notation in your use of the $ update operator to do that:
User.updateOne({
$and:[
{ userId: id },
{ posts: { $elemMatch: { title: activityTitle }}}
]},
{ $inc: { "posts.$.likes": 1 }}
)
.exec()
.then(() => {
console.log(`Liked activity '${activityTitle}'`)
})