+ const entry = undoLog.pop();
+ if (entry) {
+ redoLog.push(entry);
+ return log.recordAndApply(`${clock.now()} ${entry[0]}`);
+ }
+ },
+ redo: function () {
+ const entry = redoLog.pop();
+ if (entry) {
+ undoLog.push(entry);
+ return log.recordAndApply(`${clock.now()} ${entry[1]}`);