feature/Lagt-til-paginering-i-vinkatalogen

backend/src/index.ts

@@ -1,7 +1,27 @@
 import { ApolloServer } from "@apollo/server";
 import { startStandaloneServer } from "@apollo/server/standalone";
+import {GraphQLError} from "graphql";
 import { pool } from "./db.js";
 
+const MAX_LIMIT = 100;
+
+function readPaging(args: { limit?: number; offset?: number }) {
+  const limit = args.limit ?? 20;
+  const offset = args.offset ?? 0;
+
+  if (!Number.isInteger(limit) || limit < 1 || limit > MAX_LIMIT) {
+    throw new GraphQLError(`limit må være mellom 1 og ${MAX_LIMIT}`, {
+      extensions: { code: "BAD_USER_INPUT" },
+    });
+  }
+  if (!Number.isInteger(offset) || offset < 0) {
+    throw new GraphQLError("offset kan ikke være negativ", {
+      extensions: { code: "BAD_USER_INPUT" },
+    });
+  }
+  return { limit, offset };
+}
+
 const typeDefs = `#graphql
 
   type Wine {
@@ -75,8 +95,7 @@ const resolvers = {
       _: unknown,
       args: { limit?: number; offset?: number }
     ) => {
-      const limit = args.limit ?? 20;
-      const offset = args.offset ?? 0;
+      const { limit, offset } = readPaging(args);
 
       const winesResult = await pool.query(
         `
@@ -191,8 +210,7 @@ const resolvers = {
       _: unknown,
       args: { category: string; limit?: number; offset?: number }
     ) => {
-      const limit = args.limit ?? 20;
-      const offset = args.offset ?? 0;
+      const { limit, offset } = readPaging(args);
       const inCategory = `
         EXISTS (
           SELECT 1

client/src/components/Pagination.css

@@ -0,0 +1,43 @@
+.pagination {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  gap: 1rem;
+  margin: 2rem 0 1rem;
+}
+
+.pagination-status {
+  margin: 0;
+  color: var(--color-muted);
+}
+
+.pagination button {
+  /* At least 44x44 px, so the buttons are easy to hit on touch screens (WCAG 2.5.5) */
+  min-height: 2.75rem;
+  min-width: 2.75rem;
+  padding: 0.5rem 1rem;
+  font: inherit;
+  color: var(--color-surface);
+  background: var(--color-accent);
+  border: 2px solid var(--color-accent);
+  border-radius: 0.5rem;
+  cursor: pointer;
+}
+
+.pagination button:hover:not(:disabled) {
+  background: var(--color-text);
+  border-color: var(--color-text);
+}
+
+/* Clear focus ring for keyboard users, not shown on mouse click */
+.pagination button:focus-visible {
+  outline: 3px solid var(--color-accent);
+  outline-offset: 3px;
+}
+
+.pagination button:disabled {
+  color: var(--color-muted);
+  background: transparent;
+  border-color: var(--color-border);
+  cursor: not-allowed;
+}

client/src/components/Pagination.tsx

@@ -0,0 +1,57 @@
+import './Pagination.css';
+
+type Props = {
+  /** Current page, starting at 1 */
+  page: number;
+  totalPages: number;
+  onPageChange: (page: number) => void;
+  /** True while the next page is loading, so the user can't click twice */
+  disabled?: boolean;
+};
+
+/**
+ * Previous/next navigation between pages of results.
+ *
+ * Display only, like WineList: it knows nothing about GraphQL, it just reports
+ * which page the user wants. That makes it reusable (Find wine by food,
+ * Favourites ...) and easy to test with Vitest.
+ *
+ * Accessibility:
+ * - <nav> with aria-label, so screen reader users can jump straight to it
+ * - real <button>s, so it works with keyboard (Tab + Enter/Space) out of the box
+ * - disabled buttons at the first/last page instead of hiding them,
+ *   so the layout doesn't jump and it's clear where you are
+ */
+export default function Pagination({
+  page,
+  totalPages,
+  onPageChange,
+  disabled = false,
+}: Props) {
+  // One page or fewer: nothing to navigate between
+  if (totalPages <= 1) return null;
+
+  return (
+    <nav className="pagination" aria-label="Sidenavigering">
+      <button
+        type="button"
+        onClick={() => onPageChange(page - 1)}
+        disabled={disabled || page <= 1}
+      >
+        <span aria-hidden="true">← </span>Forrige
+      </button>
+
+      <p className="pagination-status">
+        Side {page} av {totalPages}
+      </p>
+
+      <button
+        type="button"
+        onClick={() => onPageChange(page + 1)}
+        disabled={disabled || page >= totalPages}
+      >
+        Neste<span aria-hidden="true"> →</span>
+      </button>
+    </nav>
+  );
+}

client/src/components/WineCatalog.tsx

@@ -1,8 +1,12 @@
+import { useEffect, useRef, useState } from 'react';
 import { gql } from '@apollo/client';
 import { useQuery } from '@apollo/client/react';
 import WineList from './WineList';
+import Pagination from './Pagination';
 import type { WineListItem } from '../types/wine';
 
+export const PAGE_SIZE = 20;
+
 /**
  * Fetches wines from the GraphQL backend and passes them to WineList.
  *
@@ -35,20 +39,53 @@ type WinesData = {
 };
 
 export default function WineCatalog() {
-  const { data, loading, error } = useQuery<WinesData>(WINES_QUERY, {
-    variables: { offset: 0, limit: 20 },
-  });
+  const [page, setPage] = useState(1);
+  const offset = (page - 1) * PAGE_SIZE;
+
+  const { data, previousData, loading, error } = useQuery<WinesData>(
+    WINES_QUERY,
+    { variables: { offset, limit: PAGE_SIZE } },
+  );
+
+  const shown = data ?? previousData;
+
+  const pageChanged = useRef(false);
+  useEffect(() => {
+    if (!pageChanged.current || !data) return;
+    pageChanged.current = false;
+    const heading = document.getElementById('catalog-heading');
+    heading?.focus();
+    heading?.scrollIntoView({ block: 'start' });
+  }, [data]);
+
+  function changePage(newPage: number) {
+    pageChanged.current = true;
+    setPage(newPage);
+  }
 
   // role="status" and role="alert" make screen readers announce the messages
-  if (loading) return <p role="status">Laster viner …</p>;
   if (error) {
     return <p role="alert">Kunne ikke hente viner. Prøv igjen senere.</p>;
   }
+  if (!shown) return <p role="status">Laster viner …</p>;
+
+  const totalCount = shown.wines.totalCount;
+  const totalPages = Math.ceil(totalCount / PAGE_SIZE);
 
   return (
-    <WineList
-      wines={data?.wines.items ?? []}
-      totalCount={data?.wines.totalCount ?? 0}
-    />
+    // aria-busy tells screen readers the content is being updated
+    <div aria-busy={loading}>
+      <WineList
+        wines={shown.wines.items}
+        totalCount={totalCount}
+        offset={offset}
+      />
+      <Pagination
+        page={page}
+        totalPages={totalPages}
+        onPageChange={changePage}
+        disabled={loading}
+      />
+    </div>
   );
 }

client/src/components/WineList.tsx

@@ -5,6 +5,8 @@ type Props = {
   wines: WineListItem[];
   /** Total number of wines in the database, not just the ones shown */
   totalCount: number;
+  /** How many wines come before this page (0 on the first page) */
+  offset?: number;
 };
 
 /**
@@ -21,7 +23,7 @@ type Props = {
  * - <article> per wine, labelled by the wine's name
  * - <dl>/<dt>/<dd> so each property is read with its label
  */
-export default function WineList({ wines, totalCount }: Props) {
+export default function WineList({ wines, totalCount, offset = 0 }: Props) {
   if (wines.length === 0) {
     return <p role="status">Ingen viner funnet.</p>;
   }
@@ -30,7 +32,7 @@ export default function WineList({ wines, totalCount }: Props) {
     <section aria-labelledby="catalog-heading">
       <h2 id="catalog-heading">Vinkatalog</h2>
       <p className="wine-count">
-        Viser {wines.length} av {totalCount} viner
+        Viser {offset + 1}-{offset + wines.length} av {totalCount} viner
       </p>
 
       {/*