MongoDb group if not already grouped - mongodb

Question

Trying to figure out the syntax to make a mongoDB group that would contain the documents that haven't been grouped because it didn't pass the conditional.
Document looks in part like
{
"_id" : ObjectId("value"),
"updatedAt" : ISODate("value"),
"zip" : "11209",
"state" : "NY",
"city" : "New York",
}
I created mutually exclusive string arrays for matching the other groups, like
east_ny_zipcodes = ["11209", "11210", "11211", ...]
lower_ny_zipcodes = ["11212", "11213", "11214", ...]
This is an example query from #Neal Lunn with some defined groups and values
db.zips.aggregate([
{ "$group": {
"_id": null,
"lower_ny": {
"$sum": {
"$cond": [{ "$in": [ "$zip", lower_ny_zipcodes ] },1,0]
}
},
"east_ny": {
"$sum": {
"$cond": [{ "$in": [ "$zip", east_ny_zipcodes ] },1,0]
}
},
"upper_ny": {
"$sum": {
"$cond": [{ "$in": [ "$zip", upper_ny_zipcodes ] },1,0]
}
}
}}
])
I would like to create another catch all group that would catch everything that these defined groups didn't, but also give me the documents and not just count so I can drill down into it, something like
"other_zips":{
"$push":{
"$cond": [{ "$nin": [ "$zip", lower_ny, east_ny, upper_ny,...]}]
}

Answer 1

You can try below code.
all - variable holding all zip codes
$$ROOT - complete document
The below code will push the whole document when not found else it will insert null element.
You can filter the null document in the subsequent stage if you chose.
$addToSet will keep atmost one null doc.
Documents:
"other_zips_doc":{
"$addToSet":{
"$cond": [{ $not: [ { $in: [ "$zip", all ] } ] }, "$$ROOT", null]
}
}
Count:
"other_zips_count":{
"$sum":{
"$cond": [{ $not: [ { $in: [ "$zip", all ] } ] }, 1, 0]
}
}