cache recent search results locally so re-running one is instant

frontend/app.js

@@ -83,11 +83,37 @@ function hevcCapable() {
 
 // Recent searches — device-local only (localStorage), never synced to the
 // server or another device. Most-recent-first, case-insensitive de-dupe.
+// A paired store (RESULTS_KEY) caches the actual result cards for each
+// recent query, so re-running one from the dropdown can paint instantly
+// instead of waiting on a fresh /api/search round-trip (yt-dlp, several
+// seconds). Cards are already slim ({id,title,channel,channelId,
+// channelUrl,duration,thumbnail}, server's slimEntry()) so no field
+// trimming is needed; entries are pruned to whatever's still in the query
+// list so the two stores never drift apart.
 const RecentSearches = (() => {
   const KEY = 'ytpRecentSearches';
+  const RESULTS_KEY = 'ytpRecentSearchResults';
   const MAX = 10;
+  const RESULTS_PER_QUERY_MAX = 50; // defensive cap; server returns ~45
+  const norm = (q) => (q || '').trim().toLowerCase();
   const load = () => { try { const l = JSON.parse(localStorage.getItem(KEY) || '[]'); return Array.isArray(l) ? l : []; } catch { return []; } };
   const save = (list) => { try { localStorage.setItem(KEY, JSON.stringify(list)); } catch { /* storage full / blocked */ } };
+  const loadResults = () => { try { const o = JSON.parse(localStorage.getItem(RESULTS_KEY) || '{}'); return o && typeof o === 'object' ? o : {}; } catch { return {}; } };
+  const saveResults = (obj) => {
+    try { localStorage.setItem(RESULTS_KEY, JSON.stringify(obj)); } catch {
+      // Quota exceeded — drop the (non-essential) results cache rather than
+      // risk the query-list save above also failing later.
+      try { localStorage.removeItem(RESULTS_KEY); } catch { /* storage blocked */ }
+    }
+  };
+  // Drop any cached result set whose query is no longer in `list`.
+  const pruneResults = (list) => {
+    const keep = new Set(list.map(norm));
+    const r = loadResults();
+    let changed = false;
+    for (const k of Object.keys(r)) if (!keep.has(k)) { delete r[k]; changed = true; }
+    if (changed) saveResults(r);
+  };
   return {
     list: load,
     add(q) {
@@ -95,10 +121,30 @@ const RecentSearches = (() => {
       if (!q) return;
       const list = load().filter((x) => x.toLowerCase() !== q.toLowerCase());
       list.unshift(q);
-      save(list.slice(0, MAX));
+      const trimmed = list.slice(0, MAX);
+      save(trimmed);
+      pruneResults(trimmed);
+    },
+    remove(q) {
+      const list = load().filter((x) => x.toLowerCase() !== (q || '').toLowerCase());
+      save(list);
+      pruneResults(list);
+    },
+    clear() { save([]); saveResults({}); },
+    // Cache the just-fetched result set for `q` (called on every successful search).
+    cacheResults(q, results) {
+      q = (q || '').trim();
+      if (!q || !Array.isArray(results) || !results.length) return;
+      const r = loadResults();
+      r[norm(q)] = { query: q, results: results.slice(0, RESULTS_PER_QUERY_MAX), ts: Date.now() };
+      saveResults(r);
+      pruneResults(load());
+    },
+    // Cached {query, results, ts} for `q`, or null.
+    getResults(q) {
+      const hit = loadResults()[norm(q)];
+      return hit && Array.isArray(hit.results) && hit.results.length ? hit : null;
     },
-    remove(q) { save(load().filter((x) => x.toLowerCase() !== (q || '').toLowerCase())); },
-    clear() { save([]); },
   };
 })();
 
@@ -296,6 +342,10 @@ let searchResults = [];
 // Distinguishes "never searched" (hide the list pane, show the landing) from
 // "searched and got nothing back" (keep the pane so the user sees why).
 let searchAttempted = false;
+// Bumped on every dispatched search so a slower, superseded /api/search
+// response (or background refresh — see runSearchQuery) can't clobber a
+// newer one that already landed.
+let searchSeq = 0;
 let channelData = { name: '', url: '', key: '', results: [], loading: false };
 let queue = [];                          // list of video objects for autoplay
 let queueIndex = -1;
@@ -8521,29 +8571,51 @@ function wireUI() {
   $('homePlGrid').addEventListener('scroll', updateHomeGridScrollState, { passive: true });
   window.addEventListener('resize', updateHomeGridScrollState);
 
-  els.searchForm.addEventListener('submit', async (e) => {
-    e.preventDefault();
-    const q = els.searchInput.value.trim();
+  // Runs a search, optionally painting a cached result set immediately
+  // (`instant`, from RecentSearches.getResults) before the network reply
+  // lands — the perceived-speed win for re-running a recent search.
+  // `searchSeq` guards against a slower response overwriting a newer one
+  // (the instant paint above can itself be "in flight" behind a background
+  // refresh when the user searches something else right after).
+  async function runSearchQuery(q, { instant = null } = {}) {
+    q = (q || '').trim();
     if (!q) return;
+    const mySeq = ++searchSeq;
     RecentSearches.add(q);
     hideRecentSearches();
     view = { type: 'search' };
+    if (instant) {
+      searchResults = instant.results;
+      searchAttempted = true;
+      render();
+    } else {
       render();
       showSearchSkeletons();
+    }
     // Even when already on the search view (no view change for render() to
     // detect), a new query means the user wants to see the results.
     scrollListIntoViewPortrait();
     try {
       const res = await API.search(q);
+      if (mySeq !== searchSeq) return; // superseded by a newer search
       if (!res || !res.ok) throw new Error(res?.error || 'Search failed');
-      searchResults = res.results || [];
+      const results = res.results || [];
+      searchResults = results;
       searchAttempted = true;
       renderList();
+      RecentSearches.cacheResults(q, results);
     } catch (err) {
+      if (mySeq !== searchSeq) return;
+      if (instant) return; // keep showing the cached results; fail silently
       els.cards.innerHTML = '';
       els.status.classList.remove('hidden');
       els.status.textContent = '⚠ ' + err.message;
     }
+  }
+
+  els.searchForm.addEventListener('submit', (e) => {
+    e.preventDefault();
+    runSearchQuery(els.searchInput.value);
   });
 
   // ---- Recent searches dropdown (device-local; see RecentSearches above) ----
@@ -8586,8 +8658,9 @@ function wireUI() {
     const row = e.target.closest('.search-recent-row');
     if (row) {
       e.preventDefault();
-      els.searchInput.value = row.dataset.q;
-      els.searchForm.requestSubmit();
+      const q = row.dataset.q;
+      els.searchInput.value = q;
+      runSearchQuery(q, { instant: RecentSearches.getResults(q) });
     }
   });
   document.addEventListener('click', (e) => {