feat: 新增分类

src/data/post.ts

@@ -55,3 +55,25 @@ export function getUniqueTagsWithCount(posts: CollectionEntry<"post">[]): [strin
 		),
 	].sort((a, b) => b[1] - a[1]);
 }
+
+/** Note: This function doesn't filter draft posts, pass it the result of getAllPosts above to do so. */
+export function getAllCategories(posts: Array<CollectionEntry<"post">>): string[] {
+	return posts.map((post) => post.data.category ?? "未分类");
+}
+
+/** Note: This function doesn't filter draft posts, pass it the result of getAllPosts above to do so. */
+export function getUniqueCategories(posts: Array<CollectionEntry<"post">>): string[] {
+	return [...new Set(getAllCategories(posts))];
+}
+
+/** Note: This function doesn't filter draft posts, pass it the result of getAllPosts above to do so. */
+export function getUniqueCategoriesWithCount(
+	posts: Array<CollectionEntry<"post">>,
+): Array<[string, number]> {
+	return [
+		...getAllCategories(posts).reduce(
+			(acc, t) => acc.set(t, (acc.get(t) || 0) + 1),
+			new Map<string, number>(),
+		),
+	].sort((a, b) => b[1] - a[1]);
+}