refactor: replace date formatting with native Intl.DateTimeFormat API for improved performance and accuracy

lib/format.ts

@@ -1,25 +1,55 @@
-import { UTCDate } from "@date-fns/utc";
-import { format } from "date-fns";
-
-export function formatDate(iso: string) {
+/**
+ * Formats a date string in UTC using the native Intl.DateTimeFormat API.
+ * @param iso - ISO 8601 date string or any valid date string
+ * @returns Formatted date string (e.g., "Oct 2, 2025")
+ */
+export function formatDate(iso: string): string {
   try {
     const d = new Date(iso);
     if (Number.isNaN(d.getTime())) return iso;
-    const utc = new UTCDate(d);
-    // Example: Oct. 2, 2025
-    return format(utc, "MMM. d, yyyy");
+
+    // Use Intl.DateTimeFormat for native, zero-bundle formatting
+    // Output: "Oct 2, 2025"
+    return new Intl.DateTimeFormat("en-US", {
+      month: "short",
+      day: "numeric",
+      year: "numeric",
+      timeZone: "UTC",
+    }).format(d);
   } catch {
     return iso;
   }
 }
 
-export function formatDateTimeUtc(iso: string) {
+/**
+ * Formats a date string as ISO-like datetime in UTC using native Intl.DateTimeFormat API.
+ * @param iso - ISO 8601 date string or any valid date string
+ * @returns Formatted datetime string (e.g., "2025-10-02 14:30:05 UTC")
+ */
+export function formatDateTimeUtc(iso: string): string {
   try {
     const d = new Date(iso);
     if (Number.isNaN(d.getTime())) return iso;
-    const utc = new UTCDate(d);
-    // Example: 2025-10-02 14:30:05 UTC
-    return format(utc, "yyyy-MM-dd HH:mm:ss 'UTC'");
+
+    // Use Intl.DateTimeFormat with formatToParts for precise control
+    const formatter = new Intl.DateTimeFormat("en-US", {
+      year: "numeric",
+      month: "2-digit",
+      day: "2-digit",
+      hour: "2-digit",
+      hour12: false,
+      minute: "2-digit",
+      second: "2-digit",
+      timeZone: "UTC",
+    });
+
+    const parts = formatter.formatToParts(d);
+    const partMap = Object.fromEntries(
+      parts.map((p) => [p.type, p.value]),
+    ) as Record<string, string>;
+
+    // Construct: 2025-10-02 14:30:05 UTC
+    return `${partMap.year}-${partMap.month}-${partMap.day} ${partMap.hour}:${partMap.minute}:${partMap.second} UTC`;
   } catch {
     return iso;
   }

package.json

@@ -30,7 +30,6 @@
   },
   "dependencies": {
     "@bprogress/next": "^3.2.12",
-    "@date-fns/utc": "^2.1.1",
     "@opentelemetry/api": "^1.9.0",
     "@posthog/nextjs-config": "^1.6.1",
     "@readme/http-status-codes": "^9.0.6",
@@ -66,7 +65,7 @@
     "media-chrome": "^4.16.1",
     "motion": "^12.23.24",
     "ms": "3.0.0-canary.202508261828",
-    "next": "16.0.5",
+    "next": "16.0.6",
     "next-themes": "^0.4.6",
     "pg": "^8.16.3",
     "postgres": "^3.4.7",
@@ -113,7 +112,7 @@
     "jsdom": "^27.2.0",
     "puppeteer": "24.26.1",
     "tailwindcss": "^4.1.17",
-    "tsx": "^4.20.6",
+    "tsx": "^4.21.0",
     "tw-animate-css": "^1.4.0",
     "typescript": "5.9.3",
     "vite-tsconfig-paths": "^5.1.4",