feat(lib): shelf sort/section pure helpers + formatSize extraction, table tests

frontend/src/components/ui.ts

@@ -1,5 +1,7 @@
 import type { Format } from "../api/types";
 
+export { formatSize } from "../lib/format"; // deprecated: phase-2 随阅读器清除
+
 export const btn =
   "inline-flex items-center gap-1.5 rounded-lg bg-white/[0.06] px-3 py-1.5 text-sm ring-1 ring-white/10 transition-colors hover:bg-white/[0.11] focus-visible:outline-2 focus-visible:outline-offset-2 focus-visible:outline-amber-500 active:bg-white/[0.15] disabled:cursor-not-allowed disabled:opacity-50";
 export const btnPrimary =
@@ -27,12 +29,3 @@ export const FORMAT_BADGE: Record<Format, string> = {
 export function formatBadge(fmt: Format, extra = ""): string {
   return `rounded px-1.5 py-0.5 text-[10px] font-semibold uppercase tracking-wide ring-1 ${FORMAT_BADGE[fmt]} ${extra}`;
 }
-
-export function formatSize(bytes: number): string {
-  if (bytes <= 0) return "";
-  const units = ["B", "KB", "MB", "GB"];
-  let i = 0;
-  let n = bytes;
-  for (; n >= 1024 && i < units.length - 1; i++) n /= 1024;
-  return `${n >= 10 || i === 0 ? Math.round(n) : n.toFixed(1)} ${units[i]}`;
-}

frontend/src/lib/format.ts

@@ -0,0 +1,8 @@
+export function formatSize(bytes: number): string {
+  if (bytes <= 0) return "";
+  const units = ["B", "KB", "MB", "GB"];
+  let i = 0;
+  let n = bytes;
+  for (; n >= 1024 && i < units.length - 1; i++) n /= 1024;
+  return `${n >= 10 || i === 0 ? Math.round(n) : n.toFixed(1)} ${units[i]}`;
+}

frontend/src/lib/shelf.ts

@@ -0,0 +1,19 @@
+import type { Book } from "../api/types";
+import { groupByDir } from "./group";
+
+export type SortKey = "added" | "title" | "progress";
+export const SORT_LABEL: Record<SortKey, string> = { added: "最近入库", title: "标题", progress: "阅读进度" };
+export type GroupMode = "flat" | "dir";
+
+export function sortBooks(books: Book[], key: SortKey): Book[] {
+  const a = [...books];
+  if (key === "title") return a.sort((x, y) => x.title.localeCompare(y.title, "zh"));
+  if (key === "progress") return a.sort((x, y) => y.percent - x.percent || (x.added_at < y.added_at ? 1 : x.added_at > y.added_at ? -1 : 0));
+  return a.sort((x, y) => (x.added_at < y.added_at ? 1 : x.added_at > y.added_at ? -1 : 0));
+}
+
+/** 页面分组视图:flat 一段无标题;dir 沿用「根目录置顶、目录名 locale 排序」。 */
+export function sections(books: Book[], key: SortKey, mode: GroupMode): { label: string; books: Book[] }[] {
+  if (mode === "flat") return [{ label: "", books: sortBooks(books, key) }];
+  return groupByDir(sortBooks(books, key)).map((g) => ({ label: g.dir, books: g.books }));
+}