How to group an array using reduce, without unwind+group?

[Takis]

Thank you for trying to help me,i think its not possible to group an array only by using reduce in mongoql.
I will make a new topic,asking about the root of the problem.

MongoDB missing basic document(object) operators?

Hello How to do in mongoDB document operations? Lets say that “$$mydoc” is a document and “$$mykey” is a key (variable key not literal) How to do contains?("$$mydoc","$$mykey") put("$$mydoc","$$mykey","randomValue") remove("$$mydoc","$$mykey") .... (and all those basic operation on maps that programming languages offer) The root of the problem is that in mongo seems that you can’t use variables to refer to fields. I know that i can use $function operator and javascript,but those above a…

Thank you alot