Which command is used to perform an aggregation operation in MongoDB?

The command used to perform an aggregation operation in MongoDB is the aggregate() function. This function is specifically designed to process data records and return computed results. You can use it to perform various operations like filtering, grouping, and transforming data in a single query.

The aggregate() function takes an array of stages as its argument, where each stage represents a specific operation in the aggregation pipeline. This flexibility makes it a powerful tool for complex data processing tasks, allowing developers to derive insights from their data sets efficiently.

In contrast, the other commands serve different purposes. The findOne() function retrieves a single document from a collection based on a query. The insertMany() command is used to insert multiple documents into a collection, and updateOne() is for updating a single document that matches a specified filter. While all of these commands are crucial for manipulating data in MongoDB, only aggregate() is specifically intended for performing aggregation operations.