feat: live timer since rebuild

src/_includes/layouts/base.njk

@@ -29,6 +29,7 @@
     {% include "partials/footer.njk" %}
   </div>
 
+  <script type="module" src="/assets/js/build-timer.js"></script>
   {% block scripts %}{% endblock %}
 </body>
 </html>

src/_includes/partials/footer.njk

@@ -4,6 +4,8 @@
     <span>RUNTIME: ELEVENTY 3.x STATIC</span>
     <span>&bull;</span>
     <span>THEME: NATIVE TERMINAL DARK</span>
+    <span>&bull;</span>
+    <time id="build-age" data-build-timestamp="{{ buildTimestamp }}" aria-live="polite">REBUILT: INITIALIZING</time>
   </div>
 
   <div class="footer-right">

src/assets/js/build-timer.js

@@ -0,0 +1,30 @@
+export const formatBuildAge = (buildTimestamp, nowTimestamp = new Date().toISOString()) => {
+  const buildTime = Date.parse(buildTimestamp);
+  const now = Date.parse(nowTimestamp);
+
+  if (!Number.isFinite(buildTime) || !Number.isFinite(now)) return "unknown";
+
+  const elapsedSeconds = Math.max(0, Math.floor((now - buildTime) / 1000));
+  const days = Math.floor(elapsedSeconds / 86400);
+  const hours = Math.floor((elapsedSeconds % 86400) / 3600);
+  const minutes = Math.floor((elapsedSeconds % 3600) / 60);
+  const seconds = elapsedSeconds % 60;
+
+  if (days > 0) return `${days}d ${hours}h ago`;
+  if (hours > 0) return `${hours}h ${minutes}m ago`;
+  if (minutes > 0) return `${minutes}m ${seconds}s ago`;
+  return `${seconds}s ago`;
+};
+
+if (typeof document !== "undefined") {
+  const timer = document.getElementById("build-age");
+
+  if (timer) {
+    const updateBuildAge = () => {
+      timer.textContent = `REBUILT: ${formatBuildAge(timer.dataset.buildTimestamp)}`;
+    };
+
+    updateBuildAge();
+    window.setInterval(updateBuildAge, 1000);
+  }
+}