Ark state moves to IndexedDB: raw bytes on disk, memory-fronted, write-behind.

localStorage held a deep wallet's ark state as ~700KB of JSON (UTF-16 on
disk), parsed on every boot and stringified on every save, and the wallet
cache blob carried a second ~600KB copy. src/ark/store.js keeps the state
in IndexedDB (db coinos-ark) with each coin's signed bytes as a Uint8Array,
fronted by an in-memory map so loadArkState/saveArkState stay synchronous:
reads return clones, writes coalesce (200ms) and flush immediately when the
page hides. Existing localStorage copies migrate on first open (newest _rev
wins) and are removed only after the IndexedDB write completed; no
IndexedDB means localStorage exactly as before. Records keep their
btc-wallet-cache:<id>:ark… keys, and a wallet wipe clears both stores via
the new per-feature wipeCache hook.

The ark cache extension is now syncOnly: it still rides the sync snapshot
(and the Blossom blob) but the local wallet cache no longer embeds it —
measured on a live wallet the cache blob went from 655KB to 10KB.

Verified in the live tab: all wallets migrated, bytes raw on disk, balance
and coin set unchanged, localStorage ark keys gone. tools/ark-store-test.js
covers migration by _rev, clone-on-read, write-behind, wipe and fallback.

Co-Authored-By: Claude Fable 5.1 <[email protected]>
Claude-Session: https://claude.ai/code/session_01Nw1Dijik1tLVKRM1WkU7xE

1 files changed, 8 insertions, 3 deletions

diff --git a/src/wallet.js b/src/wallet.js
index cce0a45..ae9ac1b 100644
--- a/src/wallet.js
+++ b/src/wallet.js
@@ -1809,7 +1809,9 @@ export class Wallet {
 
   // The serializable wallet state, shared by the localStorage cache and the
   // Nostr sync. savedAt lets us pick the newest copy across devices.
-  _snapshot() {
+  // forSync: include extensions that keep their own local store (syncOnly)
+  // and only ride the snapshot to reach other devices.
+  _snapshot(forSync = false) {
     return {
       v: 1,
       savedAt: Date.now(),
@@ -1821,7 +1823,7 @@ export class Wallet {
       nextReceiveIndex: this.nextReceiveIndex,
       nextChangeIndex: this.nextChangeIndex,
       feeRates: this.feeRates,
-      ...Object.assign({}, ...this._cacheExtensions.map((e) => { try { return e.save(); } catch { return {}; } })),
+      ...Object.assign({}, ...this._cacheExtensions.filter((e) => forSync || !e.syncOnly).map((e) => { try { return e.save(); } catch { return {}; } })),
     };
   }
 
@@ -1861,7 +1863,10 @@ export class Wallet {
       const xk = this._xpubCacheKey();
       if (xk !== this._cacheKey()) localStorage.setItem(xk, JSON.stringify(snap)); // watch-only mirror
     } catch {}
-    for (const fn of this._cacheSavedHooks) { try { fn(snap); } catch {} }
+    // the sync hooks see the full picture (same savedAt, so echoes still match)
+    const syncOnly = this._cacheExtensions.filter((e) => e.syncOnly);
+    const forSync = syncOnly.length ? Object.assign(snap, ...syncOnly.map((e) => { try { return e.save(); } catch { return {}; } })) : snap;
+    for (const fn of this._cacheSavedHooks) { try { fn(forSync); } catch {} }
   }
 
   restoreCache() {