Mongoose Query.prototype.nin() API

The Mongoose Query API.prototype.nin() method of the Mongoose API is used on the Query objects. It allows us to extract the documents from collection that are not equal to the expression we provide to the method as a parameter. Using this method we can fetch documents which are not equal to the values specified in the array. Let us understand nin() method using an example.

Syntax:

query.nin( path, [values] );

Parameters: This method accepts two parameters as discussed below:

• path: It is used to specify the name of the field from the collection.
• values: It is used to specify the values in the form of array.

Return Value: This method returns query object on which we can call callback function.

Setting up Node.js application:

Step 1: Create a Node.js application using the following command:

npm init

Step 2: After creating the NodeJS application, Install the required module using the following command:

npm install mongoose

Project Structure: The project structure will look like this:

Database Structure: The database structure will look like this, the following documents are present in the collection.

Example 1: In this example, we are illustrating the functionality of nin() method. We are fetching all the documents from the collection except the documents where the value of orderNumber field is not in “0,20,10”.

Filename: app.js

Javascript

// Require mongoose module
const mongoose = require("mongoose");

// Set Up the Database connection
const URI = "mongodb://localhost:27017/geeksforgeeks";

const connectionObject = mongoose.createConnection(URI, {
    useNewUrlParser: true,
    useUnifiedTopology: true,
});

const Customer = connectionObject.model(
    "Customer",
    new mongoose.Schema({
        name: String,
        address: String,
        orderNumber: Number,
    })
);

const query = Customer.find();
query.nin("orderNumber", [0, 20, 10])
query.exec((error, result) => {
    if (error) {
        console.log("Error -", error);
    } else {
        console.log("Result -", result);
    }
})

Step to run the program: To run the application execute the below command from the root directory of the project:

node app.js

Output:

Result - [
  {
    _id: new ObjectId("639ede899fdf57759087a655"),
    name: 'Chintu',
    address: 'Indore',
    orderNumber: 15,
    __v: 0
  },
  {
    _id: new ObjectId("63bcfcc2876922405349b69d"),
    name: 'Bhavesh',
    address: 'Mhow',
    orderNumber: 65,
    __v: 0
  }
]

Example 2: In this example, we are illustrating the functionality of nin() method. We are fetching all the documents from the collection except the documents where the value of rollNumber field is not in “0,00,000” and orderNumber field is not in “1000,999”.

Filename: app.js

Javascript

// Require mongoose module
const mongoose = require("mongoose");

// Set Up the Database connection
const URI = "mongodb://localhost:27017/geeksforgeeks";

const connectionObject = mongoose.createConnection(URI, {
    useNewUrlParser: true,
    useUnifiedTopology: true,
});

const Customer = connectionObject.model(
    "Customer",
    new mongoose.Schema({
        name: String,
        address: String,
        orderNumber: Number,
    })
);

const query = Customer.find();
query.nin("rollNumber", [0, 00, 000]);
query.nin("orderNumber", [1000, 999,]);
query.then((res => {
    console.log(res);
})).catch((err) => {
    console.log(err);
})

Step to run the program: To run the application execute the below command from the root directory of the project:

node app.js

Output:

[
  {
    _id: new ObjectId("639ede899fdf57759087a655"),
    name: 'Chintu',
    address: 'Indore',
    orderNumber: 15,
    __v: 0
  },
  {
    _id: new ObjectId("639ede899fdf57759087a653"),
    name: 'Aditya',
    address: 'Mumbai',
    orderNumber: 20,
    __v: 0
  },
  {
    _id: new ObjectId("63bcfcc2876922405349b69d"),
    name: 'Bhavesh',
    address: 'Mhow',
    orderNumber: 65,
    __v: 0
  }
]

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