LibJS: Implement stringification Temporal.Instant prototypes

Author: https://github.com/trflynn89
Commit: 615ad70030
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/2557
Reviewed-by: https://github.com/shannonbooth ✅

Libraries/LibJS/Tests/builtins/Temporal/Instant/Instant.prototype.toJSON.js

@@ -0,0 +1,18 @@
+describe("correct behavior", () => {
+    test("length is 0", () => {
+        expect(Temporal.Instant.prototype.toJSON).toHaveLength(0);
+    });
+
+    test("basic functionality", () => {
+        const instant = new Temporal.Instant(1625614921123456789n);
+        expect(instant.toJSON()).toBe("2021-07-06T23:42:01.123456789Z");
+    });
+});
+
+describe("errors", () => {
+    test("this value must be a Temporal.Instant object", () => {
+        expect(() => {
+            Temporal.Instant.prototype.toJSON.call("foo");
+        }).toThrowWithMessage(TypeError, "Not an object of type Temporal.Instant");
+    });
+});

Libraries/LibJS/Tests/builtins/Temporal/Instant/Instant.prototype.toLocaleString.js

@@ -0,0 +1,18 @@
+describe("correct behavior", () => {
+    test("length is 0", () => {
+        expect(Temporal.Instant.prototype.toLocaleString).toHaveLength(0);
+    });
+
+    test("basic functionality", () => {
+        const instant = new Temporal.Instant(1625614921123456789n);
+        expect(instant.toLocaleString()).toBe("2021-07-06T23:42:01.123456789Z");
+    });
+});
+
+describe("errors", () => {
+    test("this value must be a Temporal.Instant object", () => {
+        expect(() => {
+            Temporal.Instant.prototype.toLocaleString.call("foo");
+        }).toThrowWithMessage(TypeError, "Not an object of type Temporal.Instant");
+    });
+});

Libraries/LibJS/Tests/builtins/Temporal/Instant/Instant.prototype.toString.js

@@ -0,0 +1,72 @@
+describe("correct behavior", () => {
+    test("length is 0", () => {
+        expect(Temporal.Instant.prototype.toString).toHaveLength(0);
+    });
+
+    test("basic functionality", () => {
+        const instant = new Temporal.Instant(1625614921123456789n);
+        expect(instant.toString()).toBe("2021-07-06T23:42:01.123456789Z");
+    });
+
+    test("timeZone option", () => {
+        const instant = new Temporal.Instant(1625614921123456789n);
+        const options = { timeZone: "+01:30" };
+        expect(instant.toString(options)).toBe("2021-07-07T01:12:01.123456789+01:30");
+    });
+
+    test("fractionalSecondDigits option", () => {
+        const instant = new Temporal.Instant(1625614921123456000n);
+        const values = [
+            ["auto", "2021-07-06T23:42:01.123456Z"],
+            [0, "2021-07-06T23:42:01Z"],
+            [1, "2021-07-06T23:42:01.1Z"],
+            [2, "2021-07-06T23:42:01.12Z"],
+            [3, "2021-07-06T23:42:01.123Z"],
+            [4, "2021-07-06T23:42:01.1234Z"],
+            [5, "2021-07-06T23:42:01.12345Z"],
+            [6, "2021-07-06T23:42:01.123456Z"],
+            [7, "2021-07-06T23:42:01.1234560Z"],
+            [8, "2021-07-06T23:42:01.12345600Z"],
+            [9, "2021-07-06T23:42:01.123456000Z"],
+        ];
+        for (const [fractionalSecondDigits, expected] of values) {
+            const options = { fractionalSecondDigits };
+            expect(instant.toString(options)).toBe(expected);
+        }
+
+        // Ignored when smallestUnit is given
+        expect(instant.toString({ smallestUnit: "minute", fractionalSecondDigits: 9 })).toBe(
+            "2021-07-06T23:42Z"
+        );
+    });
+
+    test("smallestUnit option", () => {
+        const instant = new Temporal.Instant(1625614921123456789n);
+        const values = [
+            ["minute", "2021-07-06T23:42Z"],
+            ["second", "2021-07-06T23:42:01Z"],
+            ["millisecond", "2021-07-06T23:42:01.123Z"],
+            ["microsecond", "2021-07-06T23:42:01.123456Z"],
+            ["nanosecond", "2021-07-06T23:42:01.123456789Z"],
+        ];
+        for (const [smallestUnit, expected] of values) {
+            const options = { smallestUnit };
+            expect(instant.toString(options)).toBe(expected);
+        }
+    });
+});
+
+describe("errors", () => {
+    test("this value must be a Temporal.Instant object", () => {
+        expect(() => {
+            Temporal.Instant.prototype.toString.call("foo");
+        }).toThrowWithMessage(TypeError, "Not an object of type Temporal.Instant");
+    });
+
+    test("custom time zone doesn't have a getOffsetNanosecondsFor function", () => {
+        const instant = new Temporal.Instant(0n);
+        expect(() => {
+            instant.toString({ timeZone: null });
+        }).toThrowWithMessage(TypeError, "Invalid time zone name 'null");
+    });
+});