TimezonelessDate now throws exception for invalid dates

Author: simshadows

src/helpers/timezoneless-date.test.ts

@@ -16,6 +16,90 @@ import {TimezonelessDate} from "./timezoneless-date";
 function d(s: string): TimezonelessDate {
     return TimezonelessDate.parseISODate(s);
 }
+function d2(y: number, m: number, d: number): string {
+    return (new TimezonelessDate(y, m, d)).toISOString();
+}
+
+describe("Instantiation", () => {
+    test("Can instantiate first and last day of each month", () => {
+        function testISO(s: string) {
+            expect(d(s).toISOString()).toBe(s);
+        }
+        expect(d2(1990,  0,  1)).toBe("1990-01-01");
+        expect(d2(1991,  0, 31)).toBe("1991-01-31");
+        expect(d2(1992,  1,  1)).toBe("1992-02-01");
+        expect(d2(1993,  1, 28)).toBe("1993-02-28");
+        expect(d2(1994,  2,  1)).toBe("1994-03-01");
+        expect(d2(1995,  2, 31)).toBe("1995-03-31");
+        expect(d2(1996,  3,  1)).toBe("1996-04-01");
+        expect(d2(1997,  3, 30)).toBe("1997-04-30");
+        expect(d2(1998,  4,  1)).toBe("1998-05-01");
+        expect(d2(1999,  4, 31)).toBe("1999-05-31");
+        expect(d2(2000,  5,  1)).toBe("2000-06-01");
+        expect(d2(2001,  5, 30)).toBe("2001-06-30");
+        expect(d2(2002,  6,  1)).toBe("2002-07-01");
+        expect(d2(2003,  6, 31)).toBe("2003-07-31");
+        expect(d2(2004,  7,  1)).toBe("2004-08-01");
+        expect(d2(2005,  7, 31)).toBe("2005-08-31");
+        expect(d2(2006,  8,  1)).toBe("2006-09-01");
+        expect(d2(2007,  8, 30)).toBe("2007-09-30");
+        expect(d2(2008,  9,  1)).toBe("2008-10-01");
+        expect(d2(2009,  9, 31)).toBe("2009-10-31");
+        expect(d2(2010, 10,  1)).toBe("2010-11-01");
+        expect(d2(2011, 10, 30)).toBe("2011-11-30");
+        expect(d2(2012, 11,  1)).toBe("2012-12-01");
+        expect(d2(2013, 11, 31)).toBe("2013-12-31");
+        testISO("2014-01-01");
+        testISO("2015-01-31");
+        testISO("2016-02-01");
+        testISO("2017-02-28");
+        testISO("2018-03-01");
+        testISO("2019-03-31");
+        testISO("2020-04-01");
+        testISO("2021-04-30");
+        testISO("2022-05-01");
+        testISO("2023-05-31");
+        testISO("2024-06-01");
+        testISO("2025-06-30");
+        testISO("2026-07-01");
+        testISO("2027-07-31");
+        testISO("2028-08-01");
+        testISO("2029-08-31");
+        testISO("2030-09-01");
+        testISO("2031-09-30");
+        testISO("2032-10-01");
+        testISO("2033-10-31");
+        testISO("2034-11-01");
+        testISO("2035-11-30");
+        testISO("2036-12-01");
+        testISO("2037-12-31");
+
+        // TODO: account for leap year
+    });
+    test("Throws exception for invalid months", () => {
+        expect(() => d("1990-00-15")).toThrow();
+        expect(() => d2(1990, -1, 15)).toThrow();
+        expect(() => d("1990-13-15")).toThrow();
+        expect(() => d2(1990, 12, 15)).toThrow();
+    });
+    test("Throws exception for invalid days", () => {
+        expect(() => d("1990-01-32")).toThrow();
+        //expect(() => d("1990-02-32")).toThrow();
+        expect(() => d("1990-03-32")).toThrow();
+        expect(() => d("1990-04-31")).toThrow();
+        expect(() => d("1990-05-32")).toThrow();
+        expect(() => d("1990-06-31")).toThrow();
+        expect(() => d("1990-07-32")).toThrow();
+        expect(() => d("1990-08-32")).toThrow();
+        expect(() => d("1990-09-31")).toThrow();
+        expect(() => d("1990-10-32")).toThrow();
+        expect(() => d("1990-11-31")).toThrow();
+        expect(() => d("1990-12-32")).toThrow();
+
+        // TODO: test constructor from ISO string
+        // TODO: account for leap year
+    });
+});
 
 describe("toString()-like methods", () => {
     test("Can print a string", () => {
@@ -35,8 +119,12 @@ describe("toString()-like methods", () => {
             expect(a.toISOString()).toBe("1984-10-04");
         });
         test("Can pad the month", () => {
-            const a = new TimezonelessDate(1984, 2, 27);
-            expect(a.toISOString()).toBe("1984-03-27");
+            const a = new TimezonelessDate(1995, 2, 27);
+            expect(a.toISOString()).toBe("1995-03-27");
+        });
+        test("Can pad both", () => {
+            const a = new TimezonelessDate(2000, 3, 1);
+            expect(a.toISOString()).toBe("2000-04-01");
         });
     });
 });

src/helpers/timezoneless-date.ts

@@ -24,6 +24,17 @@ export class TimezonelessDate {
      */
     constructor(y: number, m: number, d: number) {
         this.__d = dayjs(0).year(y).month(m).date(d);
+
+        // All of this for a crude slow way of validating the date.
+        // We accept it here because we're not particularly concerned
+        // about speed, but maybe we should improve it some day.
+        const yStr = String(y).padStart(4, "0");
+        const mStr = String(m + 1).padStart(2, "0");
+        const dStr = String(d).padStart(2, "0");
+        const s = `${yStr}-${mStr}-${dStr}`;
+        if (this.toISOString() !== s) {
+            throw new Error(`Invalid date: ${s}`);
+        }
     }
 
     toString(): string {

src/pages/food/diary.mdx

@@ -108,6 +108,12 @@ I sometimes try to put in diacritics/accents or native language characters, but
     - 2021-11-10 - Ultimate Bacon Burger
 - **Da Tang Noodles** (Chinese, Noodles) - Chatswood
     - 2024-04-20 - Braised Beef Noodle Soup
+- <Ve n="Dean's Diner" c="Burgers" l="Newtown"/>
+    - <It c="burger" d="2025-08-17" n="Australian Crawl" cost="AUD 24.00 with chips"/>
+        - *"Beef pattie, beetroot, bacon, egg, cheese, lettuce, tomato, onion & sauce"*
+        - I had mine with tomato sauce + mustard sauce.
+    - <It c="sides" d="2025-08-17" n="Chips"/>
+    - <It c="drink" d="2025-08-17" n="Hippy Hippy Shake (Thickshake), Chocolate Flavoured" cost="AUD 10.00"/>
 - **Destination Roll** (Vietnamese, Banh Mi) - North Sydney
     - 2024-10-17 - Chicken Roll
 - **Don Don City** (Korean) - CBD, George St.