Mongoose findOneAndUpdate Not Returning Updated Document: Explained
In Node.js using Mongoose for MongoDB interactions, the findOneAndUpdate method is designed to locate a document based on a query and then update it with the provided changes. However, by default, it returns the original, unupdated document. This can be counterintuitive if you expect the updated document to be returned automatically.
Solution: Specifying new: true
To retrieve the updated document after the update operation, you need to explicitly tell Mongoose to return it by setting the new option to true in the query options:
const updatedDocument = await MyModel.findOneAndUpdate(query, update, { new: true });
Here's a breakdown:
MyModel: Your Mongoose model representing the collection you're working with.query: The criteria to identify the document you want to update (e.g.,{ name: 'Alice' }).update: The changes you want to make to the document (e.g.,{ $set: { age: 30 } }).{ new: true }: This option instructs Mongoose to return the updated document after the update is complete.
Understanding the Default Behavior
The default behavior of returning the original document stems from performance considerations. Retrieving the updated document from the database after the update adds an extra operation. The default approach assumes you might not always need the updated document right away, so it prioritizes efficiency.
Example: Updating a User's Name
Here's an example that demonstrates finding a user by email, updating their name, and then retrieving the updated document:
const mongoose = require('mongoose');
const userSchema = new mongoose.Schema({
email: String,
name: String
});
const User = mongoose.model('User', userSchema);
async function updateUserName(email, newName) {
try {
const updatedUser = await User.findOneAndUpdate(
{ email },
{ $set: { name: newName } },
{ new: true }
);
if (updatedUser) {
console.log(`User updated: ${updatedUser.name}`);
} else {
console.log('User not found');
}
} catch (error) {
console.error(error);
}
}
updateUserName('[email protected]', 'Alice Smith');
This code will find the user with the email [email protected], update their name to Alice Smith, and then log the updated user object to the console (assuming the update was successful).
const mongoose = require('mongoose');
const productSchema = new mongoose.Schema({
name: String,
quantity: Number
});
const Product = mongoose.model('Product', productSchema);
async function updateProductQuantity(productId, newQuantity) {
try {
const updatedProduct = await Product.findOneAndUpdate(
{ _id: productId }, // Find by product ID
{ $inc: { quantity: newQuantity } }, // Increase quantity by newQuantity
{ new: true }
);
if (updatedProduct) {
console.log(`Product quantity updated: ${updatedProduct.name} (new quantity: ${updatedProduct.quantity})`);
} else {
console.log('Product not found');
}
} catch (error) {
console.error(error);
}
}
updateProductQuantity('12345', 10); // Update product with ID '12345', increase quantity by 10
This code updates the quantity of a product based on its ID. It uses the $inc operator to increment the quantity by the specified value.
Example 2: Updating a User's Email and Address
const mongoose = require('mongoose');
const userSchema = new mongoose.Schema({
name: String,
email: String,
address: {
street: String,
city: String,
state: String
}
});
const User = mongoose.model('User', userSchema);
async function updateUser(userId, newEmail, newAddress) {
try {
const updatedUser = await User.findOneAndUpdate(
{ _id: userId }, // Find by user ID
{
$set: {
email: newEmail,
address: newAddress
}
},
{ new: true }
);
if (updatedUser) {
console.log(`User updated: ${updatedUser.name} (new email: ${updatedUser.email})`);
} else {
console.log('User not found');
}
} catch (error) {
console.error(error);
}
}
updateUser('56789', '[email protected]', { street: '123 Main St', city: 'Anytown', state: 'CA' });
This code updates a user's email and address simultaneously using the $set operator. It provides a more complex update scenario where multiple fields are modified.
- This approach involves two separate operations:
- First, use
findto locate the document based on your criteria. - Then, use
updateOne(to update a single document) orupdateMany(to update multiple documents matching the criteria) to apply the changes.
- First, use
This can be useful when you only need to update the document and don't necessarily require the updated document itself. It can also be slightly more efficient in some scenarios because it avoids the extra retrieval of the updated document.
async function updateProductQuantity(productId, newQuantity) {
try {
const product = await Product.find({ _id: productId });
if (product.length > 0) {
await Product.updateOne({ _id: productId }, { $inc: { quantity: newQuantity } });
console.log(`Product quantity updated for product ID: ${productId}`);
} else {
console.log('Product not found');
}
} catch (error) {
console.error(error);
}
}
Native MongoDB Driver with findOneAndUpdate
- If you're comfortable with the native MongoDB driver, you can bypass Mongoose and directly use the
findOneAndUpdatemethod with the driver:
const MongoClient = require('mongodb').MongoClient;
async function updateProductQuantity(productId, newQuantity) {
const client = await MongoClient.connect('mongodb://localhost:27017');
const db = client.db('your_database_name');
const collection = db.collection('products');
try {
const updatedProduct = await collection.findOneAndUpdate(
{ _id: productId },
{ $inc: { quantity: newQuantity } },
{ returnOriginal: false } // Similar to { new: true } in Mongoose
);
if (updatedProduct.value) {
console.log(`Product quantity updated: ${updatedProduct.value.name} (new quantity: ${updatedProduct.value.quantity})`);
} else {
console.log('Product not found');
}
await client.close();
} catch (error) {
console.error(error);
}
}
Custom Mongoose Query with Hooks (Advanced)
- If you need more granular control over the update process, you can create a custom query using Mongoose and leverage pre/post hooks:
const productSchema = new mongoose.Schema({ name: String, quantity: Number });
productSchema.pre('save', async function (next) {
// Perform custom logic before saving the updated document (optional)
next();
});
async function updateProductQuantity(productId, newQuantity) {
try {
const product = await Product.findOneAndUpdate(
{ _id: productId },
{ $inc: { quantity: newQuantity } }
);
if (product) {
await product.save(); // Trigger pre/post hooks (if defined)
console.log(`Product quantity updated for product ID: ${productId}`);
} else {
console.log('Product not found');
}
} catch (error) {
console.error(error);
}
}
node.js mongodb mongoose
