Creates new aggregation expression that takes the associated value and combines it with the
given values (documents or mapped objects) into a single document.
Creates new aggregation expression that takes the associated value and combines it with the
result values of the given expressions into a single document.
Creates new aggregation expression that takes the associated value and combines it with the
values of the given field references into a single document.
Creates new aggregation expression that takes the associated value and uses
$mergeObjects as an accumulator within the $group stage. NOTE: Requires MongoDB 4.0 or later.
Creates new aggregation expression that takes the associated value and combines it with the
given values (documents or mapped objects) into a single document. NOTE: Requires MongoDB 4.0 or later.
Creates new aggregation expression that takes the associated value and combines it with the
values of the given field references into a single document. NOTE: Requires MongoDB 4.0 or later.
Creates new aggregation expression that takes the associated value and combines it with the
result values of the given expressions into a single document. NOTE: Requires MongoDB 4.0 or later.
Creates new aggregation expression that takes the associated value and converts it to an
array of documents that contain two fields k and v each. NOTE: Requires MongoDB 3.6 or later.