# Constants
$currentOp.
$graphLookup.
$bucket fields.
GroupBy = "groupBy" // Declared.
$graphLookup.
$graphLookup.
$collStats.
$bucket fields.
$graphLookup.
$geoNear.
$geoNear.
$lookup fields.
$graphLookup.
JeoJSON reference: https://docs.mongodb.com/manual/reference/geojson/.
Output = "output" // Declared.
$bucket fields.
ID field is constant for referencing the "_id" field name.
$currentOp.
$currentOp.
$currentOp.
$unwind.
$geoNear.
$merge.
$geoNear.
$collStats.
$lookup fields.
JeoJSON reference: https://docs.mongodb.com/manual/reference/geojson/.
From = "from" // Declared.
$currentOp.
$graphLookup.
$geoNear.
$geoNear.
JeoJSON reference: https://docs.mongodb.com/manual/reference/geojson/.
JeoJSON reference: https://docs.mongodb.com/manual/reference/geojson/.
JeoJSON reference: https://docs.mongodb.com/manual/reference/geojson/.
$geoNear.
$replaceRoot.
$merge.
$bucket fields.
$unwind.
$lookup fields.
JeoJSON reference: https://docs.mongodb.com/manual/reference/geojson/.
JeoJSON reference: https://docs.mongodb.com/manual/reference/geojson/.
$unwind.
$geoNear.
$graphLookup.
$sample.
$geoNear.
$graphLookup.
$collStats.
$geoNear.
Let = "let" // Declared.
$merge.
# Variables
AllUsersDoc is document that contains "allUsers":true value.
Empty is a predefined empty map.
EmptyDoc is empty document.