Database
[{"make":"Toyota","color":"blue","tires":[{"make":"Mishlen","size":185},{"make":"Mishlen","size":210}]}]
Query
db.collection.aggregate([{$addFields:{tires:{$map:{input:"$tires",in:{make:"$$this.make",size:"$$this.size",matched:{$cond:{if:{$lt:["$$this.size",200]},then:true,else:false}}}}}}}])