Cache versioned habit history and load visible calendar ranges

src/components/CalendarCache.test.ts

@@ -0,0 +1,27 @@
+import { afterAll, afterEach, expect, spyOn, test } from "bun:test";
+import { CalendarCache } from "./CalendarCache";
+const fetchSpy = spyOn(globalThis, "fetch");
+afterEach(() => fetchSpy.mockReset());
+afterAll(() => fetchSpy.mockRestore());
+const range = { from: "2026-07-01", to: "2026-09-30" };
+test("calendar cache shares in-flight reads, retains wider history and invalidates changed versions", async () => {
+  fetchSpy.mockImplementation(async () => Response.json({ from: range.from, to: range.to, days: [{ date: "2026-07-01" }, { date: "2026-09-01" }] }));
+  const cache = new CalendarCache();
+  await Promise.all([cache.load("habit", "v1", range), cache.load("habit", "v1", range)]);
+  expect(fetchSpy).toHaveBeenCalledTimes(1);
+  expect(String(fetchSpy.mock.calls[0]![0])).toContain("compact=true");
+  const subset = await cache.load("habit", "v1", { from: "2026-09-01", to: range.to });
+  expect(subset.days).toHaveLength(1);
+  expect(fetchSpy).toHaveBeenCalledTimes(1);
+  await cache.load("habit", "v2", range);
+  expect(fetchSpy).toHaveBeenCalledTimes(2);
+  await new CalendarCache().load("habit", "v2", range);
+  expect(fetchSpy).toHaveBeenCalledTimes(3);
+});
+test("a failed history request can be retried without retaining a rejected cache entry", async () => {
+  fetchSpy.mockRejectedValueOnce(new Error("offline")).mockResolvedValue(Response.json({ ...range, days: [] }));
+  const cache = new CalendarCache();
+  await expect(cache.load("habit", "v1", range)).rejects.toThrow("offline");
+  await expect(cache.load("habit", "v1", range)).resolves.toMatchObject({ days: [] });
+  expect(fetchSpy).toHaveBeenCalledTimes(2);
+});