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Original Description

Description:

countDocuments function: returns the number of documents matching the filter
estimatedDocumentCount function: gets an estimate of the count of documents in a collection using collection metadata

https://github.com/mongodb/specifications/blob/master/source/crud/crud.rst#count-api-details

the count() helper is currently deprecated in the drivers, but we have not done so in the shell. There is a ticket for this: https://jira.mongodb.org/browse/SERVER-36436

Engineering Ticket Description:

countDocuments was a late change to the drivers for MongoDB 4.0 and is missing from the MongoDB Shell. Needs to be added in a future release.

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Description

Scope of changes (files that need work and how much)

Add new pages

• db.collection.countDocuments.txt
• db.collection.estimatedDocumentCount.txt

+ redirect config/redirects and toc source/includes/ref-toc-method-collection.yaml

Add references

• source/core/transactions
• source/aggregation.
• source/core/views.txt

• source/includes/extracts-views.yaml
• source/reference/command/count.txt
• source/reference/method/db.collection.count.txt
• source/reference/operator/aggregation/count.txt

Impact to other docs outside of this product

None

MVP (work and date?)

Resources (e.g. Scope Docs, Invision)