for(let i=0; i<test.length; i++;){
 db.collection('Parent').find({ "Id" : test[i].Id }).toArray(function(err, result){
  if(result.length > 0){
    db.collection('anotherCollection', function(err, collection){
      collection.insert({
        field1: test[i].field1,
        field2: test[i].field2
      })
    })
  }
})
}