From bf1b29083cb2cbe99c3ab12dd7a1dd8fa749b8e6 Mon Sep 17 00:00:00 2001
From: Arild Matsson <arild.matsson@gu.se>
Date: Wed, 24 Apr 2024 16:17:25 +0200
Subject: [PATCH] Skip old news

---
 src/home/news.service.ts |  9 +++++----
 src/util.test.ts         | 14 ++++++++++++++
 src/util.ts              | 12 ++++++++++++
 3 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/src/home/news.service.ts b/src/home/news.service.ts
index 4ececdc..c1407c1 100644
--- a/src/home/news.service.ts
+++ b/src/home/news.service.ts
@@ -1,6 +1,6 @@
 const Yaml = import("js-yaml").then((m) => m.default);
 import once from "lodash/once";
-import { retry } from "@/util";
+import { addDays, retry } from "@/util";
 import type { ByLang } from "@/util.types";
 
 const NEWS_URL: string = import.meta.env.VITE_NEWS_URL;
@@ -40,10 +40,11 @@ export const fetchAllNews = once(async (): Promise<NewsItem[]> => {
  * @throws Fetch or parse errors
  */
 export async function fetchNews(filterFeatured?: boolean): Promise<NewsItem[]> {
-  // Get news and skip items that have expired
-  // TODO Also skip items older than 6 months
+  const now = new Date();
   let items = (await fetchAllNews()).filter(
-    (item) => !item.expires || item.expires > new Date(),
+    (item) =>
+      (!item.expires || item.expires > now) && // Skip expired items
+      item.created > addDays(now, -365 / 2), // Skip items older than 6 months
   );
 
   // Filter by the "featured" tag if specified
diff --git a/src/util.test.ts b/src/util.test.ts
index d863de0..8f33ed3 100644
--- a/src/util.test.ts
+++ b/src/util.test.ts
@@ -1,5 +1,6 @@
 import { describe, expect, test } from "vitest";
 import {
+  addDays,
   enarray,
   ensureExtension,
   formatDate,
@@ -15,6 +16,19 @@ import {
   unarray,
 } from "@/util";
 
+describe("addDays", () => {
+  const d = new Date("24 April 2024 15:50 (CEST)");
+  test("across a month", () => {
+    expect(addDays(d, 10)).toEqual(new Date("4 May 2024 15:50 (CEST)"));
+    expect(addDays(d, -24)).toEqual(new Date("31 March 2024 15:50 (CEST)"));
+  });
+  test("across DST", () => {
+    // Notice the hour is different
+    expect(addDays(d, 200)).toEqual(new Date("10 November 2024 14:50 (CET)"));
+    expect(addDays(d, -25)).toEqual(new Date("30 March 2024 14:50 (CET)"));
+  });
+});
+
 describe("enarray", () => {
   test("leaves array unchanged", () => {
     expect(enarray([1, 2, 3])).toStrictEqual([1, 2, 3]);
diff --git a/src/util.ts b/src/util.ts
index ad9ee71..e544dc3 100644
--- a/src/util.ts
+++ b/src/util.ts
@@ -1,6 +1,18 @@
 import clone from "lodash/clone";
 import round from "lodash/round";
 
+/** The number of milliseconds in a full day. */
+const DAY_MS = 24 * 60 * 60 * 1000;
+
+/**
+ * Add or subtract a number of days to a date
+ *
+ * Works with 24-hour cycles, so the hour (and possibly date) will change across DST changes.
+ **/
+export function addDays(date: Date, days: number) {
+  return new Date(date.getTime() + days * DAY_MS);
+}
+
 export const sleep = (ms: number) => new Promise((r) => setTimeout(r, ms));
 
 /** Trigger a file download in the browser by adding a temporary link and click it */