How Do I Add Temporary Properties On A Mongoose Object Just For Response Which Is Not Stored In Database

When working with Mongoose, a popular Node.js MongoDB library, you may encounter situations where you need to add temporary properties to objects that aren't stored in the database but are useful for responses. This can be a handy feature when you want to include additional information in your response without modifying the actual data in your database.

Fortunately, adding temporary properties to Mongoose objects for responses only is quite straightforward. Here's how you can achieve this in a few simple steps:

1. Utilize the `virtuals` Property: Mongoose provides a feature called virtuals that allows you to add additional properties to your schema that are not persisted to the database. Virtuals are a great way to include calculated properties or transformations on your model's data.

2. Define a Virtual Property: To add a temporary property to your Mongoose object for response purposes, you can define a virtual property on your schema. Virtual properties are defined using the `Schema` object's `virtual()` method.

3. Example Code Snippet:

const mongoose = require('mongoose');

// Define your schema
const exampleSchema = new mongoose.Schema({
    name: String,
    age: Number,
});

// Define a virtual property for response purposes
exampleSchema.virtual('extraInfo').get(function() {
    return `Additional information about ${this.name}`;
});

// Create your Mongoose model
const ExampleModel = mongoose.model('Example', exampleSchema);

4. Accessing the Virtual Property:

Once you have defined the virtual property, you can access it just like any other property on your Mongoose object. For example:

const example = new ExampleModel({
    name: 'John Doe',
    age: 30,
});

console.log(example.extraInfo); // Output: Additional information about John Doe

5. Sending the Object with Temporary Property in Responses: When you send your Mongoose object as a response from your API or application, the virtual property you defined will be included in the response automatically. This can be helpful for providing additional context or calculated data without modifying the original object.

By following these steps and leveraging Mongoose's virtuals feature, you can easily add temporary properties to your Mongoose objects for responses without the need to store them in the database. This can enhance the flexibility and usefulness of your data models in various scenarios.

In conclusion, using virtual properties in Mongoose is a powerful way to extend your data models with additional information for response purposes, making your applications more dynamic and versatile. Start experimenting with virtuals in your Mongoose schemas today to unlock new possibilities in handling and presenting your data.