Lean option on Query⌗

While returning data from the database as an API response, the virtuals/methods available on a mongoose document are unnecessary. Lean option can be set on such queries to return just the data directly from the database. It also improves the overall performance of the API.

Documents returned from queries with the lean option enabled are plain javascript objects, not MongooseDocuments. They have no save method, getters/setters, or other Mongoose magic applied.

app.use(async (req, res) => {
   let users = await User.find({ status: 'active' }).limit(10).lean();
   res.json(users);
});

Hydrate method on Model⌗

Hydrating is the opposite of the lean option. Hydrate method is used to initialize a mongoose document from a plain javascript object to get access to its virtuals/methods.

let user = await User.findOne().lean();
let document = User.hydrate(user);

assert(document instanceof mongoose.Document); // true

Code Repository⌗

A working code repository is available at github. Get started in your local machine.

git clone https://github.com/abskmj/example-mongoose-lean-hydrate.git
cd example-mongoose-lean-hydrate
npm install
npm test