code: function jumpToPast(history, index) {
      if (index < 0 || index >= history.past.length) return history;
  
      const { past, future, _latestUnfiltered } = history;
  
      const newPast = past.slice(0, index);
      const newFuture = [...past.slice(index + 1), _latestUnfiltered, ...future];
      const newPresent = past[index];
  
      return newHistory(newPast, newPresent, newFuture);
  }
docs: jumpToPast: jump to requested index in past history