fix(admin): use collection urlPattern for preview button fallback URL (#181)

* fix(admin): use collection urlPattern for preview button fallback URL

The preview button hardcoded fallback URLs as /${collection}/${slug},
ignoring the collection's urlPattern setting. Collections with custom
URL patterns (e.g. urlPattern: "/biljke/{slug}" on a "biljka" collection)
would open a 404 instead of the correct page.

Thread urlPattern through the manifest and use it in the ContentEditor
preview fallback.

Fixes #167

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Signed-off-by: Filip Ilic <ilic.filip@gmail.com>

* chore: add changeset for preview URL pattern fix

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Signed-off-by: Filip Ilic <ilic.filip@gmail.com>

---------

Signed-off-by: Filip Ilic <ilic.filip@gmail.com>
Co-authored-by: Matt Kane <mkane@cloudflare.com>

.changeset/fix-preview-url-pattern.md

@@ -0,0 +1,6 @@
+---
+"@emdash-cms/admin": patch
+"emdash": patch
+---
+
+fix(admin): use collection urlPattern for preview button fallback URL

packages/admin/src/components/ContentEditor.tsx

@@ -363,6 +363,11 @@ export function ContentEditor({
 	const handlePreview = async () => {
 		if (!item?.id) return;
 
+		const contentUrl = (s: string) => {
+			const pattern = manifest?.collections[collection]?.urlPattern;
+			return pattern ? pattern.replace("{slug}", s) : `/${collection}/${s}`;
+		};
+
 		setIsLoadingPreview(true);
 		try {
 			const result = await getPreviewUrl(collection, item.id);
@@ -371,11 +376,11 @@ export function ContentEditor({
 				window.open(result.url, "_blank", "noopener,noreferrer");
 			} else {
 				// Fallback to direct URL if preview not configured
-				window.open(`/${collection}/${slug || item.id}`, "_blank", "noopener,noreferrer");
+				window.open(contentUrl(slug || item.id), "_blank", "noopener,noreferrer");
 			}
 		} catch {
 			// Fallback to direct URL on error
-			window.open(`/${collection}/${slug || item?.id}`, "_blank", "noopener,noreferrer");
+			window.open(contentUrl(slug || item?.id || ""), "_blank", "noopener,noreferrer");
 		} finally {
 			setIsLoadingPreview(false);
 		}

packages/admin/src/lib/api/client.ts

@@ -55,6 +55,7 @@ export interface AdminManifest {
 			labelSingular: string;
 			supports: string[];
 			hasSeo: boolean;
+			urlPattern?: string;
 			fields: Record<
 				string,
 				{

packages/core/src/astro/types.ts

@@ -28,6 +28,7 @@ export interface ManifestCollection {
 	labelSingular: string;
 	supports: string[];
 	hasSeo: boolean;
+	urlPattern?: string;
 	fields: Record<
 		string,
 		{

packages/core/src/emdash-runtime.ts

@@ -1180,6 +1180,7 @@ export class EmDashRuntime {
 					labelSingular: collection.labelSingular || collection.label,
 					supports: collection.supports || [],
 					hasSeo: collection.hasSeo,
+					urlPattern: collection.urlPattern,
 					fields,
 				};
 			}