MongoDB has the ability to specify the second parameter to find() function, which allows making a projection of result, by modifying it.
For example:
db.schools.find( { zipcode: "63109" },
{ students: { $elemMatch: { school: 102 } } } )The operation returns the documents that have zipcode equal to 63109 and projects the students array using $elemMatch, so it will contain the first item that match project or don't include this array at all:
{ "_id" : 1, "students" : [ { "name" : "john", "school" : 102, "age" : 10 } ] }
{ "_id" : 3 }
{ "_id" : 4, "students" : [ { "name" : "barney", "school" : 102, "age" : 7 } ] }Also it is possible to use $, $slice, 1 and 0 operators
We should make it possible to use this with Array.map, so buildFilter will also can return a mapper.
MongoDB has the ability to specify the second parameter to
find()function, which allows making a projection of result, by modifying it.For example:
The operation returns the documents that have zipcode equal to 63109 and projects the
studentsarray using $elemMatch, so it will contain the first item that match project or don't include this array at all:{ "_id" : 1, "students" : [ { "name" : "john", "school" : 102, "age" : 10 } ] } { "_id" : 3 } { "_id" : 4, "students" : [ { "name" : "barney", "school" : 102, "age" : 7 } ] }Also it is possible to use
$,$slice,1and0operatorsWe should make it possible to use this with Array.map, so buildFilter will also can return a mapper.