feat: add last updated date to blog posts

.eleventy.js

@@ -22,6 +22,7 @@ const path = require("node:path");
 const fs = require("node:fs");
 const yaml = require("js-yaml");
 const { DateTime } = require("luxon");
+const { execSync } = require("node:child_process");
 
 //-----------------------------------------------------------------------------
 // Eleventy Config
@@ -159,6 +160,27 @@ module.exports = eleventyConfig => {
 		value1.concat(value2),
 	);
 
+	eleventyConfig.addFilter("gitLastUpdated", filepath => {
+		// Only check git history in production
+		if (CONTEXT) {
+			try {
+				const date = execSync(`git log -1 --format=%cD ${filepath}`, {
+					encoding: "utf-8",
+				}).trim();
+
+				if (!date) {
+					return null;
+				}
+
+				return new Date(date);
+			} catch {
+				return null;
+			}
+		}
+
+		return null;
+	});
+
 	/**
 	 * ***************************************************************************************
 	 *  Plugins

src/_includes/partials/post-sidebar.html

@@ -10,6 +10,14 @@ <h2 class="post__sidebar-module__title">Contributors</h2>
         {% endfor %}
     </div>
 
+    {% set git_last_updated = page.inputPath | gitLastUpdated %}
+    {% set last_updated = page.date if git_last_updated and git_last_updated < page.date else git_last_updated %}
+    {% if last_updated %}
+    <div class="post__sidebar-module">
+        <h2 class="post__sidebar-module__title">Last updated <time datetime="{{ last_updated | readableDate }}">{{ last_updated | readableDate }}</time></h2>
+    </div>
+    {% endif %}
+
     {% if tags %}
     <div class="post__sidebar-module">
         <h2 class="post__sidebar-module__title">Tags</h2>