function _compressArray(json, aKeys) {
        var nIndex,
            nLenKeys;

        for (nIndex = 0, nLenKeys = json.length; nIndex < nLenKeys; nIndex++) {
            json[nIndex] = JSONC.compress(json[nIndex], aKeys);
        }
    }
Method to compress array objects
@private
@param json
@param aKeys