feat: better error messages

server/api/links/[id]/index.patch.ts

@@ -17,6 +17,11 @@ export default defineEventHandler(async (event) => {
   const params = await getValidatedRouterParams(event, paramsSchema.parse);
   const body = await readValidatedBody(event, bodySchema.parse);
 
+  const conflicts = await findConflictingFields(body, params.id);
+  if (conflicts.length > 0) {
+    throw createError({ statusCode: 409, message: `A link with this ${joinFields(conflicts)} already exists` });
+  }
+
   const [link] = await db
     .update(tables.links)
     .set(body)

server/api/links/index.post.ts

@@ -11,6 +11,12 @@ const bodySchema = z.object({
 
 export default defineEventHandler(async (event) => {
   const body = await readValidatedBody(event, bodySchema.parse);
+
+  const conflicts = await findConflictingFields(body);
+  if (conflicts.length > 0) {
+    throw createError({ statusCode: 409, message: `A link with this ${joinFields(conflicts)} already exists` });
+  }
+
   const [link] = await db.insert(tables.links).values(body).returning();
   return link;
 });

server/utils/links.ts

@@ -0,0 +1,34 @@
+import { db } from "#server/db";
+import * as tables from "#server/db/schema";
+import { and, eq, ne } from "drizzle-orm";
+
+const UNIQUE_FIELDS = ["name", "path", "url"] as const;
+type UniqueField = (typeof UNIQUE_FIELDS)[number];
+
+export const joinFields = (fields: string[]): string => {
+  if (fields.length <= 1) return fields.join("");
+  return `${fields.slice(0, -1).join(", ")} and ${fields.at(-1)}`;
+};
+
+export const findConflictingFields = async (
+  values: Partial<Record<UniqueField, string>>,
+  excludeId?: number,
+): Promise<UniqueField[]> => {
+  const conflicts: UniqueField[] = [];
+
+  for (const field of UNIQUE_FIELDS) {
+    const value = values[field];
+    if (!value) continue;
+
+    const conflict = await db.query.links.findFirst({
+      where: and(
+        eq(tables.links[field], value),
+        excludeId !== undefined ? ne(tables.links.id, excludeId) : undefined,
+      ),
+    });
+
+    if (conflict) conflicts.push(field);
+  }
+
+  return conflicts;
+};