Analytics: queued events, once-per-order revenue, heatmap on product pages (#17)

Analytics: queued events, once-per-order revenue, heatmap on product pages (#17)
Co-authored-by: Michael Czechowski <mail@librete.ch>
(cherry picked from commit d5dd109c63)

utils/trackEvent.test.ts

@@ -0,0 +1,51 @@
+import { afterEach, beforeEach, expect, test } from "bun:test";
+
+const sent: Array<[string, unknown]> = [];
+beforeEach(() => {
+	sent.length = 0;
+	(globalThis as any).window = {};
+});
+afterEach(async () => {
+	const { __resetTrackQueue } = await import("./trackEvent");
+	__resetTrackQueue();
+	delete (globalThis as any).window;
+});
+const umami = { track: (e: string, d: unknown) => sent.push([e, d]) };
+const wait = (ms: number) => new Promise((r) => setTimeout(r, ms));
+
+test("sends immediately when umami is loaded", async () => {
+	const { trackEvent } = await import("./trackEvent");
+	(globalThis as any).window.umami = umami;
+	trackEvent("a", { x: 1 });
+	expect(sent).toEqual([["a", { x: 1 }]]);
+});
+
+test("queues until umami appears, then flushes in order and calls onSent", async () => {
+	const { trackEvent } = await import("./trackEvent");
+	let confirmed = false;
+	trackEvent("first");
+	trackEvent("purchase-completed", { revenue: 12.5, currency: "EUR" }, () => (confirmed = true));
+	expect(sent).toEqual([]);
+	await wait(300);
+	(globalThis as any).window.umami = umami;
+	await wait(400);
+	expect(sent.map((s) => s[0])).toEqual(["first", "purchase-completed"]);
+	expect(confirmed).toBe(true);
+});
+
+test("never throws and drops events when umami never loads", async () => {
+	const { trackEvent } = await import("./trackEvent");
+	let confirmed = false;
+	trackEvent("lost", undefined, () => (confirmed = true));
+	await wait(10_500);
+	(globalThis as any).window.umami = umami;
+	await wait(400);
+	expect(sent).toEqual([]);
+	expect(confirmed).toBe(false);
+}, 15_000);
+
+test("is a no-op on the server", async () => {
+	delete (globalThis as any).window;
+	const { trackEvent } = await import("./trackEvent");
+	expect(() => trackEvent("ssr")).not.toThrow();
+});