[{_id:1,feeling:["dislike","like","love"]},{_id:2,feeling:["like","love","dislike","dislike"]},{_id:3,feeling:["love","love"]},]

db.collection.aggregate([{$unwind:"$feeling"},{$group:{_id:{i:"$_id",f:"$feeling"},cnt:{$sum:1}}},{$project:{_id:"$_id.i",a:[{k:"$_id.f",v:"$cnt"}]}},{$group:{_id:"$_id",s:{"$mergeObjects":{"$arrayToObject":"$a"}}}},{$replaceRoot:{newRoot:{$mergeObjects:["$s","$$ROOT"]}}},{$project:{s:0}}])