initial commit

src/game/persistence.ts

@@ -0,0 +1,51 @@
+import type { Inventory, LogDrop, TreeState, Vec2 } from './types';
+import type { UpgradeId } from './upgrades';
+
+const STORAGE_KEY = 'forest-save-v1';
+
+export interface SaveData {
+  version: 1;
+  inventory: Inventory;
+  upgradeLevels: Record<UpgradeId, number>;
+  /** World state (character/trees/logs) is optional so older saves without it still load fine —
+   * progress is restored either way, just with a freshly spawned world. */
+  character?: Vec2;
+  trees?: TreeState[];
+  logDrops?: LogDrop[];
+}
+
+function isValidSave(value: unknown): value is SaveData {
+  if (!value || typeof value !== 'object')
+    return false;
+  const data = value as Partial<SaveData>;
+  return (
+    data.version === 1
+    && typeof data.inventory === 'object' && data.inventory !== null
+    && typeof data.inventory.logs === 'number'
+    && typeof data.inventory.coins === 'number'
+    && typeof data.upgradeLevels === 'object' && data.upgradeLevels !== null
+  );
+}
+
+/** Reads the saved game from localStorage, or null if there's none / it's corrupted. */
+export function loadSave(): SaveData | null {
+  try {
+    const raw = localStorage.getItem(STORAGE_KEY);
+    if (!raw)
+      return null;
+    const parsed: unknown = JSON.parse(raw);
+    return isValidSave(parsed) ? parsed : null;
+  } catch {
+    // localStorage unavailable (private mode, disabled) or corrupted JSON — treat as no save.
+    return null;
+  }
+}
+
+/** Writes the save to localStorage. Best-effort: silently no-ops if storage is unavailable/full. */
+export function writeSave(data: SaveData): void {
+  try {
+    localStorage.setItem(STORAGE_KEY, JSON.stringify(data));
+  } catch {
+    // Ignore — e.g. private browsing mode or quota exceeded.
+  }
+}