Mongoose Aggregate.prototype.limit() API
Last Updated :
29 Dec, 2022
The Aggregate API.prototype.limit() function of the Mongoose API is used to limit the number of documents that get passed to the next stage in the aggregator pipeline.
Syntax:
Aggregate.prototype.limit()
Parameters: It accepts a single parameter as described below:
- num: It is a number that defines the maximum number of documents that get passed to the next stage.
Return type: It returns the aggregated 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.limit() method.
Example 1: In this example, we will use this method to return the first 2 documents from the response.
Filename: main.js
Javascript
const mongoose = require( 'mongoose' )
{
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,
},
age: {
type: Number,
}
});
const personsArray = [
{
name: 'Luffy' ,
age: 19
},
{
name: 'Nami' ,
age: 20
},
{
name: 'Zoro' ,
age: 35
}
]
const Person = mongoose.model( 'Person' , personSchema);
(async () => {
await Person.insertMany(personsArray);
const res = await Person.aggregate().limit(2);
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 limit the first 10 documents from the response.
Filename: main.js
Javascript
const mongoose = require( 'mongoose' )
{
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,
},
age: {
type: Number,
}
});
const personsArray = [
{
name: 'Luffy' ,
age: 19
},
{
name: 'Nami' ,
age: 20
},
{
name: 'Zoro' ,
age: 35
}
]
const Person = mongoose.model( 'Person' , personSchema);
(async () => {
await Person.insertMany(personsArray);
const res = await Person.aggregate().limit(10);
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-limit
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