Merge pull request #53 from codeforjapan/revert-29-fix/remove-tempora…

…l-pagination

Revert "fix: remove pagination temporal logic"

app/feature/search/components/SearchPagination.tsx

@@ -9,6 +9,7 @@ import Fa6SolidAngleLeft from "~icons/fa6-solid/angle-left";
 import Fa6SolidAngleRight from "~icons/fa6-solid/angle-right";
 
 import type { PaginationMeta } from "../../../generated/api/schemas/paginationMeta";
+import { buildPaginationMeta } from "../pagination";
 import type { noteSearchParamSchema } from "../validation";
 
 type PaginationProps = {
@@ -28,16 +29,18 @@ export const SearchPagination = ({
   visibleItemCount,
   ...groupProps
 }: PaginationProps) => {
+  const pagination = buildPaginationMeta(meta, currentQuery);
+
   const pageFirstItemIndex = currentQuery.offset + 1;
   const totalDisplayedItems = currentQuery.offset + visibleItemCount;
 
   const prevTo = useMemo(
-    () => (meta?.prev ? withQuery("/", getQuery(meta.prev)) : null),
-    [meta?.prev],
+    () => (pagination?.prev ? withQuery("/", getQuery(pagination.prev)) : null),
+    [pagination?.prev],
   );
   const nextTo = useMemo(
-    () => (meta?.next ? withQuery("/", getQuery(meta.next)) : null),
-    [meta?.next],
+    () => (pagination?.next ? withQuery("/", getQuery(pagination.next)) : null),
+    [pagination?.next],
   );
 
   const [clickedButton, setClickedButton] = useState<"prev" | "next">();

app/feature/search/pagination.test.ts

@@ -0,0 +1,85 @@
+import { getQuery } from "ufo";
+import { describe, expect, test } from "vitest";
+import type { z } from "zod";
+
+import type { PaginationMeta } from "../../generated/api/schemas/paginationMeta";
+import { buildPaginationMeta } from "./pagination";
+import type { noteSearchParamSchema } from "./validation";
+
+describe("buildPaginationMeta", () => {
+  test("API 修正前ロジック: 現在のクエリパラメータから PaginationMeta を生成できる", () => {
+    const currentQuery = {
+      post_includes_text: "地震",
+      limit: 10,
+      offset: 10,
+    } satisfies z.infer<typeof noteSearchParamSchema>;
+
+    // API が limit, offset 以外のクエリパラメータを削除してしまう挙動を再現
+    const currentBrokenMeta = {
+      next: "https://example.com/api/v1/data/search?offset=20&limit=10",
+      prev: "https://example.com/api/v1/data/search?offset=0&limit=10",
+    } satisfies PaginationMeta;
+
+    const paginationMeta = buildPaginationMeta(currentBrokenMeta, currentQuery);
+    const prevQuery = paginationMeta.prev
+      ? getQuery(paginationMeta.prev)
+      : null;
+    const nextQuery = paginationMeta.next
+      ? getQuery(paginationMeta.next)
+      : null;
+
+    expect(prevQuery).toStrictEqual({
+      limit: "10",
+      offset: "0",
+      post_includes_text: "地震",
+    });
+    expect(nextQuery).toStrictEqual({
+      limit: "10",
+      offset: "20",
+      post_includes_text: "地震",
+    });
+  });
+
+  test("API 修正前ロジック: offset が 0 より大きい AND limit より小さい場合も prev を生成できる", () => {
+    const currentQuery = {
+      post_includes_text: "地震",
+      limit: 15,
+      offset: 10,
+    } satisfies z.infer<typeof noteSearchParamSchema>;
+
+    // API が limit, offset 以外のクエリパラメータを削除してしまう挙動を再現
+    const currentBrokenMeta = {
+      next: "https://example.com/api/v1/data/search?offset=25&limit=15",
+      prev: "https://example.com/api/v1/data/search?offset=0&limit=15",
+    } satisfies PaginationMeta;
+
+    const fixedMeta = buildPaginationMeta(currentBrokenMeta, currentQuery);
+    const prevQuery = fixedMeta.prev ? getQuery(fixedMeta.prev) : null;
+
+    expect(prevQuery).toStrictEqual({
+      limit: "15",
+      offset: "0",
+      post_includes_text: "地震",
+    });
+  });
+
+  test("API 修正前ロジック: 前のページが存在しない場合に prev が null になる", () => {
+    const currentQuery = {
+      post_includes_text: "地震",
+      limit: 10,
+      offset: 0,
+    } satisfies z.infer<typeof noteSearchParamSchema>;
+
+    // API が limit, offset 以外のクエリパラメータを削除してしまう挙動を再現
+    const currentBrokenMeta = {
+      next: "https://example.com/api/v1/data/search?offset=10&limit=10",
+      prev: null,
+    } satisfies PaginationMeta;
+
+    const fixedMeta = buildPaginationMeta(currentBrokenMeta, currentQuery);
+
+    const prevQuery = fixedMeta.prev ? getQuery(fixedMeta.prev) : null;
+
+    expect(prevQuery).toBe(null);
+  });
+});

app/feature/search/pagination.ts

@@ -0,0 +1,50 @@
+import { parseURL, stringifyParsedURL, withQuery } from "ufo";
+import type { z } from "zod";
+
+import type { PaginationMeta } from "../../generated/api/schemas/paginationMeta";
+import type { noteSearchParamSchema } from "./validation";
+
+/**
+ * API 側のページネーション情報が正しい情報を返すようになるまで、現在のパラメータから次のページと前のページの URL を生成する
+ * @param meta
+ * API が返したページネーション情報。前後ページが存在するかどうかの確認にのみ使用する
+ * @param currentQuery
+ * 現在のクエリパラメータ
+ * @returns
+ * 修正後のページネーション情報
+ */
+// API が正常な PaginationMeta を返すようになったらこの巻数で計算する必要はない
+export const buildPaginationMeta = (
+  meta: PaginationMeta,
+  currentQuery: z.infer<typeof noteSearchParamSchema>,
+): PaginationMeta => {
+  const { limit, offset, ...rest } = currentQuery;
+
+  if (meta.next == null && meta.prev == null) {
+    return {
+      next: null,
+      prev: null,
+    };
+  }
+
+  const nextOffset = offset + limit;
+
+  // offset が 0: 前のページが存在しない
+  // offset が 10, limit が 15: 前のページが存在する
+  const prevOffset = Math.max(offset - limit, 0);
+
+  const isFirstPage = offset === 0;
+
+  // 必ず prev か next が存在する
+  // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+  const url = parseURL((meta.prev ?? meta.next)!);
+  url.search = "";
+  const baseUrl = stringifyParsedURL(url);
+
+  return {
+    next: withQuery(baseUrl, { ...rest, limit, offset: nextOffset }),
+    prev: isFirstPage
+      ? null
+      : withQuery(baseUrl, { ...rest, limit, offset: prevOffset }),
+  };
+};