Create and retrieve "multi-level" data in JSON - json

Question

For a course exercise, a friend of mine has to dynamize a website with a JSON. The problem occurs when I try to search for data on several levels. Basically, Elles wants to allow to choose ornaments. There are handles or screw covers available, and there are two of each. The problem is that I can't properly structure my JSON to make this possible, or to retrieve the data.
{
"id" : 4,
"nom":"Cercueil Les Borgia",
"description": "Ce cercueil demi-tombeau en chêne massif , vous propose de le personnaliser en s'inspirant des jardins les plus fleuris mais aussi les plus dangereux",
"prix" : 800 ,
"image" :"medias/chenemassif1.png" ,
"motifs":
[
{
"natureMo":"Fleur",
"prixMo": "30",
"disponibiliteMo":true
},
{
"natureMo":"Vichy",
"prixMo": "30",
"disponibiliteMo":true
}
],
"couleurs":
[
{
"nomCo": "Vert clair",
"code": "#93C97F"
},
{
"nomCo": "Violet",
"code": "#64527A"
}
],
"ornements": [
{
"types": [
{
"Poignées": [
{
"style": "Romaine",
"prixOr": 22,
"disponibiliteOr":true
},
{
"style":"Flamme Eco",
"prixOr":22,
"disponibiliteOr":true
}
]
},
{
"Cache-vis" : [
{
"style":"Roseau",
"prixOr":18,
"disponibiliteOr":true
},
{
"style":"Hexagonale",
"prixOr":18,
"disponibiliteOr":false
}
]
}
]
}
]
}
I've tried to put both ornament types in one type category, and use it, but that doesn't work either when I try to retrieve the data.
res += '<h3>Ornements</h3>';
for(l=0; l<doc[i].ornements.length; l++){
var ornementsNaCer = doc[i].ornements[l].types;
res += '<h4>'+ ornementsNaCer +'</h4>';