json - Why I cant get nested data from mongodb in Jade? -

i'm stuck trying info "product" , "channel" mongo object. have "cannot read property 'length' of undefined" while looping through nested array of objects:

{     "_id": objectid("579f14f0661cf39cc86c75be"),     "category": "slim"         {             "_id": objectid("579f14f0661cf39cc86c75bf"),             "country": "at",             "elems": [{                 "chanell": "atd",                 "produkt": "prod a"             }, {                 "chanell": "rtb",                 "produkt": "prod b"             }, {                 "chanell": "seo",                 "produkt": "prod c"             }]         } {             "_id": objectid("579f14f0661cf39cc86c75c0"),             "country": "de",             "elems": [{                 "chanell": "atd",                 "produkt": "prod a"             }, {                 "chanell": "rtb",                 "produkt": "prod b"             }, {                 "chanell": "seo",                 "produkt": "prod c"             }]         }  

jade query:

block content   h3.     products   div     p first pargraph       - each item in productlist         p country: #{item.country}           - each elem in item.elems             p #{elem.channell}             p #{elem.produkt} 

output:

typeerror: /var/www/html/projects/bartek/ang/produkty/public/views/productlist.jade:10    8|       - each item in productlist     9|         p country: #{item.country}   > 10|           - each elem in item.elems     11|             p #{elem.channell}     12|             p #{elem.produkt}  cannot read property 'length' of undefined 

and node code:

var collection = db.collection('slim');          collection.find({}).toarray(function(err,result){             if (err) {                 res.send(err);             } else if (result.length) {                 res.render('productlist',{                  'productlist' : result                    })             } 

at level "country" works fine - country displayed properly. item "item.elems" alone shows array of objects: [object object],[object object],[object object].