feat: sort slides listing by date DESC, title DESC as tiebreaker

app/slides/slidesData.test.ts

@@ -0,0 +1,63 @@
+import { describe, it, expect } from "vitest"
+import { compareSlides, type SlideData } from "./slidesData"
+
+function makeSlide(slug: string, timestamp: string, title: string): SlideData {
+	return { slug, metadata: { title, description: "", author: "", timestamp } }
+}
+
+describe("compareSlides", () => {
+	it("sorts newer timestamps first", () => {
+		const older = makeSlide("a", "2024-01-01T00:00:00Z", "A")
+		const newer = makeSlide("b", "2025-06-15T00:00:00Z", "B")
+		expect(compareSlides(newer, older)).toBeLessThan(0)
+		expect(compareSlides(older, newer)).toBeGreaterThan(0)
+	})
+
+	it("uses title DESC as tiebreaker for equal timestamps", () => {
+		const slideA = makeSlide("a", "2024-01-01T00:00:00Z", "Alpha")
+		const slideZ = makeSlide("z", "2024-01-01T00:00:00Z", "Zulu")
+		expect(compareSlides(slideZ, slideA)).toBeLessThan(0)
+		expect(compareSlides(slideA, slideZ)).toBeGreaterThan(0)
+	})
+
+	it("returns 0 for identical timestamp and title", () => {
+		const s1 = makeSlide("a", "2024-01-01T00:00:00Z", "Same")
+		const s2 = makeSlide("b", "2024-01-01T00:00:00Z", "Same")
+		expect(compareSlides(s1, s2)).toBe(0)
+	})
+
+	it("pushes slides with missing timestamp to the end", () => {
+		const valid = makeSlide("a", "2024-01-01T00:00:00Z", "A")
+		const noTs = makeSlide("b", "", "B")
+		expect(compareSlides(valid, noTs)).toBeLessThan(0)
+		expect(compareSlides(noTs, valid)).toBeGreaterThan(0)
+	})
+
+	it("pushes slides with invalid timestamp to the end", () => {
+		const valid = makeSlide("a", "2024-01-01T00:00:00Z", "A")
+		const invalid = makeSlide("b", "not-a-date", "B")
+		expect(compareSlides(valid, invalid)).toBeLessThan(0)
+		expect(compareSlides(invalid, valid)).toBeGreaterThan(0)
+	})
+
+	it("sorts two invalid-timestamp slides by title DESC", () => {
+		const alpha = makeSlide("a", "", "Alpha")
+		const zulu = makeSlide("z", "", "Zulu")
+		expect(compareSlides(zulu, alpha)).toBeLessThan(0)
+		expect(compareSlides(alpha, zulu)).toBeGreaterThan(0)
+	})
+
+	it("sorts a full array correctly", () => {
+		const slides = [
+			makeSlide("old", "2023-01-01T00:00:00Z", "Old Talk"),
+			makeSlide("no-ts", "", "No Timestamp"),
+			makeSlide("new", "2025-06-15T00:00:00Z", "New Talk"),
+			makeSlide("same-a", "2024-06-01T00:00:00Z", "Alpha"),
+			makeSlide("same-z", "2024-06-01T00:00:00Z", "Zulu")
+		]
+
+		const sorted = [...slides].sort(compareSlides)
+		const slugOrder = sorted.map((s) => s.slug)
+		expect(slugOrder).toEqual(["new", "same-z", "same-a", "old", "no-ts"])
+	})
+})

app/slides/slidesData.ts

@@ -77,7 +77,25 @@ export function getSlideData(slug: string): SlideData | null {
 	}
 }
 
+export function compareSlides(a: SlideData, b: SlideData): number {
+	const aTime = Date.parse(a.metadata?.timestamp)
+	const bTime = Date.parse(b.metadata?.timestamp)
+	const aValid = !isNaN(aTime)
+	const bValid = !isNaN(bTime)
+
+	if (aValid && !bValid) return -1
+	if (!aValid && bValid) return 1
+	if (!aValid && !bValid) return (b.metadata?.title ?? "").localeCompare(a.metadata?.title ?? "")
+
+	if (aTime !== bTime) return bTime - aTime
+
+	return (b.metadata?.title ?? "").localeCompare(a.metadata?.title ?? "")
+}
+
 export function getAllSlides(): SlideData[] {
 	const slugs = getAllSlideSlugs()
-	return slugs.map((slug) => getSlideData(slug)).filter((data): data is SlideData => data !== null)
+	return slugs
+		.map((slug) => getSlideData(slug))
+		.filter((data): data is SlideData => data !== null)
+		.sort(compareSlides)
 }