var store = {};

for (var i = 0; i < 110; i++) {
    var len = Math.floor(Math.random() * 500) + 1;
    json[i].Items = [];
    for (var z = 0; z < len; z++) {
        var itemFromStore = Math.floor(Math.random() * 3175),
            itemCopy = {};
        for (var prop in storeFromJson[itemFromStore]) {
            itemCopy[prop] = storeFromJson[itemFromStore][prop];
        }
        itemCopy.quantity = Math.floor(Math.random() * 40) + 1;
        json[i].Items.push(itemCopy);
    }
}
function changeStore(currentStore) {
    for (var i = 0; i < currentStore.length; i++) {
        var fullName = currentStore[i].fullName;
        store[fullName] = currentStore[i];
    }
}
changeStore(storeFromJson);