Save & load

The engine serializes everything needed to resume a playthrough — ctx, current scene, action index, locale, undo stack — into a single JSON object. Save it anywhere; restore with one call.

The headless way

// Save
const snapshot = engine.getSnapshot();
localStorage.setItem("save", JSON.stringify(snapshot));

// Load
const raw = JSON.parse(localStorage.getItem("save")!);
engine.loadSnapshot(raw); // Zod-validated + auto-migrated

Snapshots are versioned. When you change scene shape or add new state fields, register a migration:

engine.registerMigration(2, (data) => ({
  ...data,
  ctx: { ...data.ctx, reputation: 0 }, // default for new field
  schemaVersion: 3,
}));

Old saves flow through the migration pipeline transparently on load.

The React way

The SaveManager + useSaveSlots hook wraps snapshots in a slot UI:

import { SaveManager, useSaveSlots } from "@kata-framework/react";

const saveManager = new SaveManager({
  storage: localStorage,          // any StorageAdapter (localStorage, IndexedDB, custom)
  namespace: "my-game",
  slotCount: 5,
});

function SaveMenu() {
  const { slots, save, load, clear } = useSaveSlots(saveManager);
  return (
    <ul>
      {slots.map((slot, i) => (
        <li key={i}>
          {slot ? `${slot.sceneId} — ${new Date(slot.timestamp).toLocaleString()}` : "Empty"}
          <button onClick={() => save(i)}>Save</button>
          <button onClick={() => load(i)} disabled={!slot}>Load</button>
          <button onClick={() => clear(i)} disabled={!slot}>Clear</button>
        </li>
      ))}
    </ul>
  );
}

Swap the StorageAdapter to move saves into IndexedDB, a server, or a cloud sync layer.

Try it live

Rewind

For quick “whoops, go back one line” behavior, use the built-in undo stack instead of a save slot:

const engine = new KataEngine(initialCtx, { historyDepth: 100 });
engine.next();
engine.next();
engine.back(); // restores ctx, scene, action index

The undo stack is included in snapshots, so rewind capability survives save/load.

Next: Publish your game →