LibJS: Implement Temporal.PlainDateTime.prototype.with* methods

Includes with, withCalendar, and withPlainTime.

Libraries/LibJS/Tests/builtins/Temporal/PlainDateTime/PlainDateTime.prototype.with.js

@@ -0,0 +1,83 @@
+describe("correct behavior", () => {
+    test("length is 1", () => {
+        expect(Temporal.PlainDateTime.prototype.with).toHaveLength(1);
+    });
+
+    test("basic functionality", () => {
+        const plainDateTime = new Temporal.PlainDateTime(1970, 1, 1);
+        const values = [
+            [{ year: 2021 }, new Temporal.PlainDateTime(2021, 1, 1)],
+            [{ year: 2021, month: 7 }, new Temporal.PlainDateTime(2021, 7, 1)],
+            [{ year: 2021, month: 7, day: 6 }, new Temporal.PlainDateTime(2021, 7, 6)],
+            [{ year: 2021, monthCode: "M07", day: 6 }, new Temporal.PlainDateTime(2021, 7, 6)],
+            [
+                { hour: 18, minute: 14, second: 47 },
+                new Temporal.PlainDateTime(1970, 1, 1, 18, 14, 47),
+            ],
+            [
+                {
+                    year: 2021,
+                    month: 7,
+                    day: 6,
+                    hour: 18,
+                    minute: 14,
+                    second: 47,
+                    millisecond: 123,
+                    microsecond: 456,
+                    nanosecond: 789,
+                },
+                new Temporal.PlainDateTime(2021, 7, 6, 18, 14, 47, 123, 456, 789),
+            ],
+        ];
+        for (const [arg, expected] of values) {
+            expect(plainDateTime.with(arg).equals(expected)).toBeTrue();
+        }
+
+        // Supplying the same values doesn't change the date/time, but still creates a new object
+        const plainDateTimeLike = {
+            year: plainDateTime.year,
+            month: plainDateTime.month,
+            day: plainDateTime.day,
+            hour: plainDateTime.hour,
+            minute: plainDateTime.minute,
+            second: plainDateTime.second,
+            millisecond: plainDateTime.millisecond,
+            microsecond: plainDateTime.microsecond,
+            nanosecond: plainDateTime.nanosecond,
+        };
+        expect(plainDateTime.with(plainDateTimeLike)).not.toBe(plainDateTime);
+        expect(plainDateTime.with(plainDateTimeLike).equals(plainDateTime)).toBeTrue();
+    });
+});
+
+describe("errors", () => {
+    test("this value must be a Temporal.PlainDateTime object", () => {
+        expect(() => {
+            Temporal.PlainDateTime.prototype.with.call("foo");
+        }).toThrowWithMessage(TypeError, "Not an object of type Temporal.PlainDateTime");
+    });
+
+    test("argument must be an object", () => {
+        expect(() => {
+            new Temporal.PlainDateTime(1970, 1, 1).with("foo");
+        }).toThrowWithMessage(TypeError, "Object must be a partial Temporal object");
+        expect(() => {
+            new Temporal.PlainDateTime(1970, 1, 1).with(42);
+        }).toThrowWithMessage(TypeError, "Object must be a partial Temporal object");
+    });
+
+    test("argument must have one of 'day', 'hour', 'microsecond', 'millisecond', 'minute', 'month', 'monthCode', 'nanosecond', 'second', 'year'", () => {
+        expect(() => {
+            new Temporal.PlainDateTime(1970, 1, 1).with({});
+        }).toThrowWithMessage(TypeError, "Object must be a partial Temporal object");
+    });
+
+    test("argument must not have 'calendar' or 'timeZone'", () => {
+        expect(() => {
+            new Temporal.PlainDateTime(1970, 1, 1).with({ calendar: {} });
+        }).toThrowWithMessage(TypeError, "Object must be a partial Temporal object");
+        expect(() => {
+            new Temporal.PlainDateTime(1970, 1, 1).with({ timeZone: {} });
+        }).toThrowWithMessage(TypeError, "Object must be a partial Temporal object");
+    });
+});

Libraries/LibJS/Tests/builtins/Temporal/PlainDateTime/PlainDateTime.prototype.withCalendar.js

@@ -0,0 +1,13 @@
+describe("correct behavior", () => {
+    test("length is 1", () => {
+        expect(Temporal.PlainDateTime.prototype.withCalendar).toHaveLength(1);
+    });
+
+    test("basic functionality", () => {
+        const calendar = "gregory";
+        const firstPlainDateTime = new Temporal.PlainDateTime(1, 2, 3);
+        expect(firstPlainDateTime.calendarId).not.toBe(calendar);
+        const secondPlainDateTime = firstPlainDateTime.withCalendar(calendar);
+        expect(secondPlainDateTime.calendarId).toBe(calendar);
+    });
+});

Libraries/LibJS/Tests/builtins/Temporal/PlainDateTime/PlainDateTime.prototype.withPlainTime.js

@@ -0,0 +1,20 @@
+describe("correct behavior", () => {
+    test("length is 0", () => {
+        expect(Temporal.PlainDateTime.prototype.withPlainTime).toHaveLength(0);
+    });
+
+    test("basic functionality", () => {
+        const firstPlainDateTime = new Temporal.PlainDateTime(1, 2, 3, 4, 5, 6, 7, 8, 9);
+        const plainTime = new Temporal.PlainTime(10, 11, 12, 13, 14, 15);
+        const secondPlainDateTime = firstPlainDateTime.withPlainTime(plainTime);
+        expect(secondPlainDateTime.year).toBe(1);
+        expect(secondPlainDateTime.month).toBe(2);
+        expect(secondPlainDateTime.day).toBe(3);
+        expect(secondPlainDateTime.hour).toBe(10);
+        expect(secondPlainDateTime.minute).toBe(11);
+        expect(secondPlainDateTime.second).toBe(12);
+        expect(secondPlainDateTime.millisecond).toBe(13);
+        expect(secondPlainDateTime.microsecond).toBe(14);
+        expect(secondPlainDateTime.nanosecond).toBe(15);
+    });
+});