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

The Query.prototype.getUpdate() function is used to return the current update operations as a JSON object. It is easy to use and user can easily get the current update operations.

Syntax:

Query.prototype.getUpdate()

Parameters: This function has no parameter.
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:

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.updateOne({name:"Gourav"},
                             { $set: { name: 'Geek' } });
console.log(query.getUpdate());

Run index.js file using below command: 

node index.js

Output:

{ '$set': { name: 'Geek' } }

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.updateOne({name:"Gourav"},
                             { $set: { name: 'NewGeek' } });
console.log(query.getUpdate());

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:

Server listening on PORT 3000
{ '$set': { name: 'NewGeek' } }

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