Mongoose findByIdAndUpdate destroys missing fields - node.js

Question

Developing a node.js api. I have mongo data that shows venues. It contains an address, for example....
"address": {
"street": "123 main st",
"city": "seomwhere",
"state": "FL",
"zip": "33222"
},
:
When I POST to the update endpoint and send the body like this it does update the address, but it REMOVES all the other fields that were there....
"address": {
"zip": "33222"
}
So, in the db, street, city, state are missing. Here's a piece of my code...
venue = await Venue.findByIdAndUpdate(req.params.id, req.body, {
new: true,
runValidators: true
});
Any ideas why?

Answer 1

Because address contains only single key in the body ("address": { "zip": "33222" }) it replaces the other values inside the address object with the blank ones in the database.
So to overcome the issue you have to use . notation with the address object. Like
venue = await Venue.findByIdAndUpdate(
req.params.id,
{ $set: { "address.zip": "33222" },
{ new: true, runValidators: true }
)
But as you cannot identify which keys inside the address object will be updated and also for the root level
const object = req.body
for (var key in req.body.address) {
object[`address.${key}`] = object.address[key]
}
delete object.address
venue = await Venue.findByIdAndUpdate(
req.params.id,
{ $set: object },
{ new: true, runValidators: true }
)

Answer 2

You are overwriting existing address fields when not specified in the request body.
You need to only update the fields in the request body:
const fields = {};
Object.keys(req.body.address).forEach(key => {
fields[`address.${key}`] = req.body.address[key];
});
const venue = await Venue.findByIdAndUpdate(req.params.id, fields, {
new: true,
runValidators: true
});
Let's say we have this venue document:
{
"_id": "5e047d4e10be4f0da4c61703",
"name": "Venue 1",
"address": {
"street": "123 main st",
"city": "seomwhere",
"state": "FL",
"zip": "33222"
},
"__v": 0
}
When you use a requset body like this:
{
"address": {
"zip": "33333"
}
}
The response will be:
{
"address": {
"street": "123 main st",
"city": "seomwhere",
"state": "FL",
"zip": "33333"
},
"_id": "5e047d4e10be4f0da4c61703",
"name": "Venue 1",
"__v": 0
}
And when we want to update like this:
{
"address": {
"state": "NY",
"zip": "44444"
}
}
The response will be:
{
"address": {
"street": "123 main st",
"city": "seomwhere",
"state": "NY",
"zip": "44444"
},
"_id": "5e047d4e10be4f0da4c61703",
"name": "Venue 1",
"__v": 0
}