From 1994ed174d425a3ac8a5631522ed0da298b103dc Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Thu, 16 Apr 2026 14:40:58 +0000
Subject: [PATCH] perf: precalculate search strings and formatting to remove
 loop bottlenecks

Co-authored-by: MrAlokTech <107493955+MrAlokTech@users.noreply.github.com>
---
 .jules/bolt.md |  3 +++
 script.js      | 40 ++++++++++++++++++++++++++++++----------
 2 files changed, 33 insertions(+), 10 deletions(-)
 create mode 100644 .jules/bolt.md

diff --git a/.jules/bolt.md b/.jules/bolt.md
new file mode 100644
index 0000000..14e6d7c
--- /dev/null
+++ b/.jules/bolt.md
@@ -0,0 +1,3 @@
+## $(date +%Y-%m-%d) - [Pre-calculating Derived Data in Loops]
+**Learning:** Recalculating dates (`new Date()`, `.toLocaleDateString()`) and deriving search indices (`toLowerCase().includes()`) inline within render loops (e.g. `renderPDFs` and `createPDFCard`) creates a massive performance bottleneck for vanilla JS apps, significantly degrading list filtering performance when datasets are large.
+**Action:** When working with derived runtime state, compute and append these values (like `_searchStr`, `_isNew`, and `_formattedDate`) *once* immediately after fetching the data from the database or cache. Crucially, apply these transient properties *after* persisting to localStorage to avoid bloating the cache size.
diff --git a/script.js b/script.js
index 22f399d..96d86dc 100644
--- a/script.js
+++ b/script.js
@@ -416,6 +416,30 @@ async function syncClassSwitcher() {
     renderSemesterTabs();
 }
 
+// ⚡ Bolt: Pre-calculate derived search strings and date formatting once during load
+// instead of recalculating inside the high-frequency renderPDFs/createPDFCard loops.
+// This avoids expensive inline string manipulation and object instantiation overhead.
+function prepareSearchIndex(pdfs) {
+    const formatter = new Intl.DateTimeFormat("en-US", {
+        year: "numeric", month: "short", day: "numeric"
+    });
+    const now = new Date();
+    const ONE_WEEK = 7 * 24 * 60 * 60 * 1000;
+
+    pdfs.forEach(pdf => {
+        pdf._searchStr = `${pdf.title || ""} ${pdf.description || ""} ${pdf.category || ""} ${pdf.author || ""}`.toLowerCase();
+
+        const uploadDateObj = new Date(pdf.uploadDate);
+        if (!isNaN(uploadDateObj)) {
+            pdf._isNew = (now - uploadDateObj) < ONE_WEEK;
+            pdf._formattedDate = formatter.format(uploadDateObj);
+        } else {
+            pdf._isNew = false;
+            pdf._formattedDate = "Unknown Date";
+        }
+    });
+}
+
 async function loadPDFDatabase() {
     if (isMaintenanceActive) return;
 
@@ -454,6 +478,7 @@ async function loadPDFDatabase() {
 
         if (shouldUseCache) {
             pdfDatabase = cachedData;
+            prepareSearchIndex(pdfDatabase);
             // --- FIX: CALL THIS TO POPULATE UI ---
             syncClassSwitcher();
             renderSemesterTabs();
@@ -477,6 +502,8 @@ async function loadPDFDatabase() {
             data: pdfDatabase
         }));
 
+        prepareSearchIndex(pdfDatabase);
+
         // --- FIX: CALL THIS TO POPULATE UI ---
         syncClassSwitcher();
         renderPDFs();
@@ -918,10 +945,7 @@ function renderPDFs() {
             matchesCategory = currentCategory === 'all' || pdf.category === currentCategory;
         }
 
-        const matchesSearch = pdf.title.toLowerCase().includes(searchTerm) ||
-            pdf.description.toLowerCase().includes(searchTerm) ||
-            pdf.category.toLowerCase().includes(searchTerm) ||
-            pdf.author.toLowerCase().includes(searchTerm);
+        const matchesSearch = !pdf._searchStr ? false : pdf._searchStr.includes(searchTerm);
 
         // Update return statement to include matchesClass
         return matchesSemester && matchesClass && matchesCategory && matchesSearch;
@@ -994,9 +1018,7 @@ function createPDFCard(pdf, favoritesList, index = 0, highlightRegex = null) {
     const heartIconClass = isFav ? 'fas' : 'far';
     const btnActiveClass = isFav ? 'active' : '';
 
-    const uploadDateObj = new Date(pdf.uploadDate);
-    const timeDiff = new Date() - uploadDateObj;
-    const isNew = timeDiff < (7 * 24 * 60 * 60 * 1000); // 7 days
+    const isNew = pdf._isNew !== undefined ? pdf._isNew : false;
 
     const newBadgeHTML = isNew
         ? `<span style="background:var(--error-color); color:white; font-size:0.6rem; padding:2px 6px; border-radius:4px; margin-left:8px; vertical-align:middle;">NEW</span>`
@@ -1011,9 +1033,7 @@ function createPDFCard(pdf, favoritesList, index = 0, highlightRegex = null) {
     const categoryIcon = categoryIcons[pdf.category] || 'fa-file-pdf';
 
     // Formatting Date
-    const formattedDate = new Date(pdf.uploadDate).toLocaleDateString('en-US', {
-        year: 'numeric', month: 'short', day: 'numeric'
-    });
+    const formattedDate = pdf._formattedDate || "Unknown Date";
 
     // Uses global escapeHtml() now