The Aggregate API.prototype.match() function of the Mongoose API is used to find the existing documents in the database that matches the conditions mentioned in the arguments of the API.
Syntax:
Aggregate.prototype.match()
Parameters: It accepts the following 4 parameters as mentioned above and described below:
- args: It is a mongoose object which identifies match conditions for the operator.
Return type: It returns the matched documents as a response.
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
The below examples will demonstrate the Mongoose Aggregate API.prototype.match() method.
Example 1: In this example, we will use this method to find existing documents that have the name “Luffy”.
const mongoose = require('mongoose')
// Database connection {
dbName: 'event_db',
useNewUrlParser: true,
useUnifiedTopology: true
}, err => err ? console.log(err)
: console.log('Connected to database'));
const personSchema = new mongoose.Schema({
name: {
type: String,
select: false
},
age: {
type: Number,
}
}); const personsArray = [ {
name: 'Luffy',
age: 19
},
{
name: 'Nami',
age: 30
},
{
name: 'Zoro',
age: 35
}
] const Person = mongoose.model('Person', personSchema);
(async () => { await Person.insertMany(personsArray);
const res = await Person.aggregate()
.match({ name: 'Luffy' });
console.log({ res });
})() |
Step to Run Application: Run the application using the following command from the root directory of the project:
node main.js
Output:
GUI Representation of the Database using MongoDB Compass:
Example 2: In this example, we will use this method to find existing documents that have the name either “Nami” or “Zoro”.
const mongoose = require('mongoose')
// Database connection {
dbName: 'event_db',
useNewUrlParser: true,
useUnifiedTopology: true
}, err => err ? console.log(err)
: console.log('Connected to database'));
const personSchema = new mongoose.Schema({
name: {
type: String,
select: false
},
age: {
type: Number,
}
}); const personsArray = [ {
name: 'Luffy',
age: 19
},
{
name: 'Nami',
age: 30
},
{
name: 'Zoro',
age: 35
}
] const Person = mongoose.model('Person', personSchema);
(async () => { await Person.insertMany(personsArray);
const res = await Person.aggregate()
.match({ name: { $in: ['Nami', 'Zoro'] } });
console.log({ res });
})() |
Step to Run Application: Run the application using the following command from the root directory of the project:
node main.js
Output:
GUI Representation of the Database using MongoDB Compass:
Reference: https://mongoosejs.com/docs/api/aggregate.html#aggregate_Aggregate-match