Mongoose count() Function
The Query.prototype.count() function is used to count the number of documents in a collection. This functions basically specifies this query as a count query.
Syntax:
Query.prototype.count()
Parameters: This function accepts one array parameter i.e. callback function.
Return Value: This function returns Query Object.
Installation of mongoose module:
npm install mongoose
- After installing the mongoose module, you can check your mongoose version in command prompt using the command.
npm version mongoose
- 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:
Example 1: Filename: index.js
javascript
const mongoose = require( 'mongoose' );
useNewUrlParser: true ,
useCreateIndex: true ,
useUnifiedTopology: true
});
const User = mongoose.model( 'User' , {
name: { type: String },
age: { type: Number }
});
var query = User.find();
query.count( function (err, count) {
if (err) console.log(err)
else console.log( "Count is" , count)
});
|
Steps to run the program:
- The project structure will look like this:
- Run index.js file using below command:
node index.js
Output:
Count is 4
Example 2: Filename: index.js
javascript
const express = require( 'express' );
const mongoose = require( 'mongoose' );
const app = express()
useNewUrlParser: true ,
useCreateIndex: true ,
useUnifiedTopology: true
});
const User = mongoose.model( 'User' , {
name: { type: String },
age: { type: Number }
});
var query = User.find();
query.count( function (err, count) {
if (err) console.log(err)
else console.log( "Count:" , count)
});
app.listen(3000, function (error ) {
if (error) console.log(error)
console.log( "Server listening on PORT 3000" )
});
|
Steps to run the program:
- The project structure will look like this:
- Run index.js file using below command:
node index.js
Output:
Server listening on PORT 3000
Count: 4
Reference: https://mongoosejs.com/docs/api/query.html#query_Query-count
Last Updated :
10 Sep, 2020
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