How does maxScan() work in Mongoose ?

The maxScan() function is used to specify the maxScan option. This option tell the MongoDB server to set the maximum limit of scanning documents when it performs scan operation.

Syntax:

maxScan()

Parameters: This function has one val parameter of number type.
Return Value: This function returns Query Object.

Installing mongoose module:

npm install mongoose

After installing the mongoose module, you can check your mongoose version in command prompt using the command. 

npm mongoose --version

After that, you can just create a folder and add a file for example, index.js as shown below.

Database: The sample database used here is shown below: 

Project Structure: The project structure will look like this: 

Example 1:

index.js

const mongoose = require('mongoose');

// Database connection
mongoose.connect('mongodb://127.0.0.1:27017/geeksforgeeks', {
    useNewUrlParser: true,
    useCreateIndex: true,
    useUnifiedTopology: true
});

// User model
const User = mongoose.model('User', {
    name: { type: String },
    age: { type: Number }
});

const query = User.find();
query.where().maxScan(100)

console.log("Max Scan set to", query.options)

Run index.js file using below command: 

node index.js

Output:

Max Scan set to { maxScan: 100 }

Example 2:

index.js

const express = require('express');
const mongoose = require('mongoose');
const app = express()

// Database connection
mongoose.connect('mongodb://127.0.0.1:27017/geeksforgeeks', {
    useNewUrlParser: true,
    useCreateIndex: true,
    useUnifiedTopology: true
});

// User model
const User = mongoose.model('User', {
    name: { type: String },
    age: { type: Number }
});

const query = User.find();
query.where().maxScan(55)

console.log("Max Scan value:", query.options)

app.listen(3000, function(error ) {
    if(error) console.log(error)
    console.log("Server listening on PORT 3000")
});

Run index.js file using below command: 

node index.js

Output:

Max Scan value: { maxScan: 55 }
Server listening on PORT 3000

Reference:
https://mongoosejs.com/docs/api/query.html#query_Query-maxScan