tile json not caching

[jamiechong]

As far as I can tell, the JSON tile files aren't being cached. You have

        if ((typeof jsonCache[cellx] !== 'undefined') &&
            (typeof jsonCache[cellx][celly] !== 'undefined') &&
            (typeof jsonCache[cellx][celly][zoom] !== 'undefined'))
        {
            // Cache hit
            console.log('cache hit');
            handleJson (x, y, jsonCache[cellx][celly][zoom], callback);
            return;
        }

But I don't see this getting set with a successfully loaded json file anywhere in the source. The closes it gets is this:

                handleJson (x, y, json[zoom], callback);
                if (typeof jsonCache[cellx] === 'undefined') {
                    jsonCache[cellx] = {};
                }
                jsonCache[cellx][celly] = json;

This is perhaps where the bug is - maybe it needs to be

                handleJson (x, y, json[zoom], callback);
                if (typeof jsonCache[cellx] === 'undefined') {
                    jsonCache[cellx] = {};
                }
                if (typeof jsonCache[cellx][celly] === 'undefined') {
                    jsonCache[cellx][celly] = {};
                }
                jsonCache[cellx][celly][zoom] = json;

I can't tell if this is intentional or not. Would be great if you could review.