Updating DB Shema in Express JS with Mongoose library - node.js

Question

I have created a Mongo DB schema with Mongoose in Express.js and I am building the REST API. However when I try to update existing records the values that I do not update from the schema automatically become null. I understand why this happens just not sure exactly how it should be coded.
This is the route:
router.patch("/:projectId", async (req, res) => {
try {
const updatedProject = await Project.updateOne(
{ _id: req.params.projectId },
{
$set: {
title: req.body.title,
project_alias: req.body.project_alias,
description: req.body.description
}
}
);
res.json(updatedProject);
} catch (err) {
res.json({ message: err });
}
});
also here is the schema:
const ProjectsSchema = mongoose.Schema({
title: {
type: String,
required: true,
unique: true
},
project_alias: {
type: String,
unique: true,
required: true
},
description: String,
allowed_hours: Number,
hours_recorded: {
type: Number,
default: 0
},
date_added: {
type: Date,
default: Date.now
}
});
My problem is that when I want to update just the title:
{
"title" : "Title Updated33"
}
description and alias become null. Should I implement a check?

Answer 1

Just use req.body for the update object like this:
router.patch("/:projectId", async (req, res) => {
try {
const updatedProject = await Project.updateOne(
{ _id: req.params.projectId },
req.body
);
res.json(updatedProject);
} catch (err) {
res.json({ message: err });
}
});
Or even better, create a helper function like this so that we can exclude the fields in the body that doesn't exist in the model:
const filterObj = (obj, ...allowedFields) => {
const newObj = {};
Object.keys(obj).forEach(el => {
if (allowedFields.includes(el)) newObj[el] = obj[el];
});
return newObj;
};
router.patch("/:projectId", async (req, res) => {
const filteredBody = filterObj(
req.body,
"title",
"project_alias",
"description",
"allowed_hours",
"hours_recorded"
);
try {
const updatedProject = await Project.updateOne(
{ _id: req.params.projectId },
filteredBody
);
res.json(updatedProject);
} catch (err) {
res.json({ message: err });
}
});