How to populate my model with async/await syntax? - node.js

Question

I read many similar posts,mostly examples are with callbacks. I am trying to create a comment and add it to my Post.
const Post = require('./models/Post');
const Comment = require('./models/Comment');
const newLocal = 'mongodb://localhost/postdb';
mongoose.connect(newLocal, {
useNewUrlParser: true,
useUnifiedTopology: true,
}).then(() => console.log('Successfully connect to MongoDB.'))
.catch((err) => console.error('Connection error', err));
async function readP() {
try {
const comment = await Comment.create(
{title : 'Boa tarde',
body: 'Adriana bonita',
postedBy : mongoose.Types.ObjectId("5f96e440f47c1d211e84d712")
});
const post = await Post.findOne({ title: 'BJohnson'}).
populate( {path : 'comment'},
);
} catch (err) {
console.log(err);
}
}
readP();
PostSchema
const PostSchema = new mongoose.Schema({
title: String,
body: String,
createdAt: {
type: Date,
default: Date.now,
},
postedBy: {
type: mongoose.Schema.Types.ObjectId,
ref: 'User',
},
comments: [{
type: mongoose.Schema.Types.ObjectId,
ref: 'Comment',
}]
});
BJohnson post
{ "_id" : ObjectId("5fa13e1523e71045227bf74d"), "comments" : [ ObjectId("5fa13e1523e71045227bf74c") ]
Comment was created but it was not added to Post. How to specify path in a proper manner?

Answer 1

You can use findOneAndUpdate(). In your case it will find the Post and update the Post with commentId.
I'm assuming your Post Schema looks somewhat similar to this -
const mongoose = require('mongoose')
const PostSchema = new mongoose.Schema({
title: String,
body: String,
createdAt: {
type: Date,
default: Date.now,
},
postedBy: {
type: mongoose.Schema.Types.ObjectId,
ref: 'User',
},
comments: [{
type: mongoose.Schema.Types.ObjectId,
ref: 'Comment',
}]
});
module.exports = PostSchema
const Post = require('./models/Post');
const Comment = require('./models/Comment');
const newLocal = 'mongodb://localhost/postdb';
mongoose.connect(newLocal, {
useNewUrlParser: true,
useUnifiedTopology: true,
}).then(() => console.log('Successfully connect to MongoDB.'))
.catch((err) => console.error('Connection error', err));
async function readP() {
try {
const comment = await Comment.create(
{title : 'Boa tarde',
body: 'Adriana bonita',
postedBy : mongoose.Types.ObjectId("5f96e440f47c1d211e84d712")
});
const post = await Post.findOne({ title: 'BJohnson'})
const commentIds = post.comments || [] // get all the comment Id's of the post
commentIds.push(comment.id) // Push the new comment id to existing comment Id's
const updatedPost = await Post.findOneAndUpdate({ title: 'BJohnson'}, {comments: commentIds}).populate({path : 'comment'});
} catch (err) {
console.log(err);
}
}
readP();