Mongoose Document.prototype.$isNew API
The Document API.prototype.$isNew property of the Mongoose API is used on the Document model. It allows us verify whether a document is newly created. When a document is create using new keyword that document object is considered as a new document. Using this concept mongoose decides while saving the document which method it should call insertOne() or updateOne(). Let us understand $isNew property using an example.
Syntax:
document.$isNew
Parameters: This property does not accepts any property.
Return Value: This property returns Boolean value. If the document is created using new keyword than, It will return true else false.
Setting up Node.js Mongoose Module:
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 have established a database connection using mongoose and defined model over userSchema, having five columns or fields “_id”, “name”, “fixedDeposit”, “interest”, and “tenure”. We are creating new document using new keyword, at the end we are using isNew property on newUser User model object which is created using new keyword.
Filename: app.js
Javascript
const mongoose = require( "mongoose" );
useNewUrlParser: true ,
useUnifiedTopology: true ,
});
const userSchema = new mongoose.Schema({
name: String,
fixedDeposit: Number,
interest: Number,
tenure: Number
});
const User = mongoose.model( 'User' , userSchema);
const newUser = new User(
{
name: 'Denial' , fixedDeposit: 20000,
interest: 0.025, tenure: 16
}
);
console.log(newUser.isNew);
|
Step to run the program: To run the application execute the below command from the root directory of the project:
node app.js
Output:
true
Example 2: In this example, we have established a database connection using mongoose and defined model over userSchema, having five columns or fields “_id”, “name”, “fixedDeposit”, “interest”, and “tenure”. We are creating new User model document using create() method, at the end we are accessing isNew property to verify whether this document object is being created using new keyword or not.
Filename: app.js
Javascript
const mongoose = require( "mongoose" );
useNewUrlParser: true ,
useUnifiedTopology: true ,
});
const userSchema = new mongoose.Schema({
name: String,
fixedDeposit: Number,
interest: Number,
tenure: Number
});
const User = mongoose.model( 'User' , userSchema);
User.create(
{
name: 'Eric' , fixedDeposit: 10000,
interest: 0.01, tenure: 12
}
)
.then(newDocument => {
console.log(newDocument.isNew);
});
|
Step to run the program: To run the application execute the below command from the root directory of the project:
node app.js
Output:
false
Reference: https://mongoosejs.com/docs/api/document.html#document_Document-$isNew
Last Updated :
09 Dec, 2022
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