Added protecting hooks

src/modules/hooks/trackSlugHistory.ts

@@ -0,0 +1,38 @@
+import type { CollectionBeforeChangeHook } from 'payload'
+
+/**
+ * When a document's slug changes, appends the OLD slug to a `slugHistory` array
+ * field. The project reads slugHistory to serve a 301 redirect from old URLs to
+ * the current one — so changing a slug doesn't 404 the old address (a real SEO
+ * loss / audit finding).
+ *
+ * Requires a `slugHistory` field on the collection:
+ *   { name: 'slugHistory', type: 'array', fields: [{ name: 'slug', type: 'text' }],
+ *     admin: { readOnly: true } }
+ *
+ *   hooks: { beforeChange: [trackSlugHistoryHook] }
+ *
+ * The project then, in resolveRoute or a redirect check, looks up slugHistory and
+ * 301s to the current slug. See docs/hooks.md.
+ */
+export const trackSlugHistoryHook: CollectionBeforeChangeHook = ({ data, originalDoc }) => {
+  const oldSlug = originalDoc?.slug
+  const newSlug = data.slug
+  if (
+    typeof oldSlug === 'string' &&
+    typeof newSlug === 'string' &&
+    oldSlug !== newSlug &&
+    oldSlug.length > 0
+  ) {
+    const history: Array<{ slug: string }> = Array.isArray(data.slugHistory)
+      ? data.slugHistory
+      : Array.isArray(originalDoc?.slugHistory)
+        ? originalDoc.slugHistory
+        : []
+    // Avoid duplicates; don't record the new slug itself.
+    if (!history.some((h) => h?.slug === oldSlug)) {
+      data.slugHistory = [...history, { slug: oldSlug }]
+    }
+  }
+  return data
+}