How to count the number of documents in a mongodb collection

Question

I would like to know how to count the number of documents in a collection. I tried the follow

var value = collection.count(); && var value = collection.find().count() && var value = collection.find().dataSize() 

I always get method undefined.

Can you let me know what is the method to use to find the total documents in a collection.

Answer 1

Traverse to the database where your collection resides using the command:

use databasename; 

Then invoke the count() function on the collection in the database.

var value = db.collection.count(); 

and then print(value) or simply value, would give you the count of documents in the collection named collection.

Refer: http://docs.mongodb.org/v2.2/tutorial/getting-started-with-the-mongo-shell/

Answer 2

If you want the number of documents in a collection, then use the count method, which returns a Promise. Here's an example:

let coll = db.collection('collection_name'); coll.count().then((count) => {     console.log(count); }); 

This assumes you're using Mongo 3.

Edit: In version 4.0.3, count is deprecated. use countDocument to achieve the goal.