How does Query.prototype.and() work in Mongoose ?

The Query.prototype.and() specifies arguments for a $and condition. The array parameter contains all the conditions that has to be matched.
Syntax:

Query.prototype.and()

Parameters: This function has one array parameter i.e. an array of conditions.
Return Value: This function returns Query Object.

Installing mongoose : 

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: 

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.collection(User.collection);

query.and([{ name: 'Gourav' }, { age: 10 }])
.exec(function(error, result) {
    if (error) {
        console.log(error)
    } else {
        console.log(result)
    }
});

The project structure will look like this:

Run index.js file using below command: 

node index.js

Output:

[ { _id: 5ebb9129a99bde77b2efb809, name: ‘Gourav’, age: 10, __v: 0 } ]

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.collection(User.collection);

query.and([{ name: 'Lalit' }, { age: 25 }])
.exec(function(error, result) {
    if (error) {
        console.log(error)
    } else {
        console.log(result)
    }
});

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

The project structure will look like this:

Run index.js file using below command: 

node index.js

Output:

Server listening on PORT 3000
[ { _id: 5ebc3669a99bde77b2efb9ba, name: ‘Lalit’, age: 25, __v: 0 } ]

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