Updating array of objects inside an object mongodb node

I have a mongoDb model defined as follows:-

var mongoose = require("mongoose");

const postModel = new mongoose.Schema({
    postId: {
        type: String,
        unique: true,
        required: true
    },
    authorId: {
        type: String,
        required: true
    },
    post: {
        authorHandle: {
            type: String,
            required: true
        },
        heading: {
            type: String,
            required: true
        },
        message: {
            type: String,
            required: true
        },
        creationDate: {
            type: Date,
            required: true
        },
        image: { type: Array }, 
        video: { type: Array },
        comments: {
            type: Array
        }
    }
});

module.exports = mongoose.model("postModel", postModel);

Now I have a sample value of a document of the above model, suppose:-

postId: "aaa",
authorId: "bbb",
post: {
  authorHandle: "someone#123",
  heading: "hello",
  message: "post 1",
  creationDate: "some creation date string(please ignore this is irrelevant to my question)",
  image: [],
  video: [],
  comments: [
   { commentId: "1", message: "Something", createdAt: sometime },
   { commentId: "2", message: "Something else", createdAt: sometime2 },
   { commentId: "3", message: "Something other", createdAt: sometime3 },
  ]
}

Now say the user wants to update the comment with commentId 2 of this post with postId "aaa". My question is that what is the best way to use the findOneAndUpdate() method to solve this problem?

const PostModel = require("./models/PostModel"); //just importing the model that is defined above
//the below is happening inside a request handler in Node + Express
PostModel.findOneAndUpdate(
  //what to do here
)

What I have tried is pulling out that whole object and replacing it with a new object with the new message. But that doesnt seem like a very efficient way. Any and all help is greatly appreciated!

>Solution :

You should write:

const updatedPost = await PostModel.findOneAndUpdate(
  { postId: 'aaa', 'post.comments.commentId': 2 },
  { 'post.comments.$.message': 'Updated message'},
  { new: true }
)