fix: date picker improvements (#793)

* use vue component for date picker

* zero out database fields even when set to 0001-xx-xx

* fix wrong datetime display + improved datepicker

* fix ts error

* zero out times

* add date-fns to dependencies

frontend/lib/datelib/datelib.test.ts

@@ -0,0 +1,43 @@
+import { describe, test, expect } from "vitest";
+import { format, zeroTime, factorRange, parse } from "./datelib";
+
+describe("format", () => {
+  test("should format a date as a string", () => {
+    const date = new Date(2020, 1, 1);
+    expect(format(date)).toBe("2020-02-01");
+  });
+
+  test("should return the string if a string is passed in", () => {
+    expect(format("2020-02-01")).toBe("2020-02-01");
+  });
+});
+
+describe("zeroTime", () => {
+  test("should zero out the time", () => {
+    const date = new Date(2020, 1, 1, 12, 30, 30);
+    const zeroed = zeroTime(date);
+    expect(zeroed.getHours()).toBe(0);
+    expect(zeroed.getMinutes()).toBe(0);
+    expect(zeroed.getSeconds()).toBe(0);
+  });
+});
+
+describe("factorRange", () => {
+  test("should return a range of dates", () => {
+    const [start, end] = factorRange(10);
+    // Start should be today
+    expect(start).toBeInstanceOf(Date);
+    expect(start.getFullYear()).toBe(new Date().getFullYear());
+
+    // End should be 10 days from now
+    expect(end).toBeInstanceOf(Date);
+    expect(end.getFullYear()).toBe(new Date().getFullYear());
+  });
+});
+
+describe("parse", () => {
+  test("should parse a date string", () => {
+    const date = parse("2020-02-01");
+    expect(date).toBeInstanceOf(Date);
+  });
+});