LibJS: Implement Array.prototype.toSorted()

Userland/Libraries/LibJS/Tests/builtins/Array/Array.prototype-generic-functions.js

@@ -348,4 +348,10 @@ describe("ability to work with generic non-array objects", () => {
         expect(result).toEqual([undefined, "baz", undefined, "bar", "foo"]);
         expect(result).not.toBe(o);
     });
+
+    test("toSorted", () => {
+        const result = Array.prototype.toSorted.call(o);
+        expect(result).toEqual(["bar", "baz", "foo", undefined, undefined]);
+        expect(result).not.toBe(o);
+    });
 });

Userland/Libraries/LibJS/Tests/builtins/Array/Array.prototype.toSorted.js

@@ -0,0 +1,53 @@
+describe("normal behavior", () => {
+    test("length is 1", () => {
+        expect(Array.prototype.toSorted).toHaveLength(1);
+    });
+
+    test("basic functionality", () => {
+        const a = [2, 4, 1, 3, 5];
+        const b = a.toSorted();
+        expect(a).not.toBe(b);
+        expect(a).toEqual([2, 4, 1, 3, 5]);
+        expect(b).toEqual([1, 2, 3, 4, 5]);
+    });
+
+    test("custom compare function", () => {
+        const a = [2, 4, 1, 3, 5];
+        const b = a.toSorted(() => 0);
+        expect(a).not.toBe(b);
+        expect(a).toEqual([2, 4, 1, 3, 5]);
+        expect(b).toEqual([2, 4, 1, 3, 5]);
+    });
+
+    test("is unscopable", () => {
+        expect(Array.prototype[Symbol.unscopables].toSorted).toBeTrue();
+        const array = [];
+        with (array) {
+            expect(() => {
+                toSorted;
+            }).toThrowWithMessage(ReferenceError, "'toSorted' is not defined");
+        }
+    });
+});
+
+describe("errors", () => {
+    test("null or undefined this value", () => {
+        expect(() => {
+            Array.prototype.toSorted.call();
+        }).toThrowWithMessage(TypeError, "ToObject on null or undefined");
+
+        expect(() => {
+            Array.prototype.toSorted.call(undefined);
+        }).toThrowWithMessage(TypeError, "ToObject on null or undefined");
+
+        expect(() => {
+            Array.prototype.toSorted.call(null);
+        }).toThrowWithMessage(TypeError, "ToObject on null or undefined");
+    });
+
+    test("invalid compare function", () => {
+        expect(() => {
+            [].toSorted("foo");
+        }).toThrowWithMessage(TypeError, "foo is not a function");
+    });
+});