toJSON of its own properties or properties found at key/key-namespace-string.
@method sjl.stdlib.Config#toJSON
@param keyOrNsString {String} - Optional.
@returns {JSON}
function (keyOrNsString) {
                return sjl.jsonClone(
                    sjl.notEmptyAndOfType(keyOrNsString, String) ?
                       sjl.searchObj(keyOrNsString, this) : this
                );
            }