node.js - Mongoose select array item in array -

i'm having issue trying select array element id without having parent id. using following example, want select section _id of 5 save change it. here looks like:

site: {   menus: [     {       _id: 1       sections:[         { _id: 1 },         { _id: 2 },         { _id: 3 },         { _id: 4 }       ]     },     {       _id: 2       sections:[         { _id: 5 }       ]     }   ] }  schemas.site.findone({ _id: req.session.siteid, 'menus.sections._id': req.params.sectionid }).select('menus.$.sections').exec(function(err, site){   if (err) return next(err);    var section = site.menus[0].sections.id(req.params.sectionid);   // update things   section.whatever = something;   // save changes   site.save(); }); 

the problem works in first menus array, not in second. if try on second menu section (_id: 5), updates in first menu. i'm sure have close problem selecting. these arrays, not embedded models.

update: seems selection working fine. when console.log out section variable, has proper item in array. problem happens when save called. overwrites wrong item. have no save middleware running.

i have working using menuid , sectionid now. updated this:

var menu = site.menus.id(req.body.menuid),     section = menu.sections.id(req.params.sectionid); 

i leave question unanswered bit in case there better way without needing menuid.