This is a package that allows developer to write queries for MongoDB using R functions instead of properly formated character strings.
This is original find query
query <- "{ _id: ObjectId(something_that_needs_to_be_substituted_in__your_code)}"
This is rfastmongo approach
query <-find(ObjectId(my_varaible))
Mongo operators are avaialble as functions without dollar sign in front of them $set, $setOnInsert, $setOnUpdate, $each, $gt