db={Order:[{"_id":"02a33b9a-284c-4869-885e-d46981fdd679","context":{"products":[{"id":"e68fc86a-b4ad-4588-b182-ae9ee3db25e4","version":"2020-03-14T13:18:41.296+00:00"}],},}],Product:[{"_id":"e68fc86a-b4ad-4588-b182-ae9ee3db25e4","context":{"name":"My Product","image":"someimage"},}]}

db.Order.aggregate([{$lookup:{from:"Product",localField:"context.products.id",foreignField:"_id",as:"productDetails"}},{$addFields:{productDetails:{$map:{input:"$productDetails",in:{_id:"$$this._id",name:"$$this.context.name"}}}}},{$project:{_id:1,"context.products":{$map:{input:"$context.products",as:"prod",in:{$mergeObjects:["$$prod",{$arrayElemAt:[{$filter:{input:"$productDetails",cond:{$eq:["$$this._id","$$prod.id"]}}},0]}]}}}}}])