LibJS: Implement rawJSON and isRawJSON functions

Author: https://github.com/aplefull
Commit: 223c9c91e6
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/4451
Reviewed-by: https://github.com/trflynn89 ✅

Libraries/LibJS/Tests/builtins/JSON/JSON.rawJSON.js

@@ -0,0 +1,57 @@
+test("JSON.rawJSON basic functionality", () => {
+    expect(Object.isExtensible(JSON.rawJSON)).toBeTrue();
+    expect(typeof JSON.rawJSON).toBe("function");
+    expect(Object.getPrototypeOf(JSON.rawJSON)).toBe(Function.prototype);
+    expect(Object.getOwnPropertyDescriptor(JSON.rawJSON, "prototype")).toBeUndefined();
+
+    expect(JSON.stringify(JSON.rawJSON(1))).toBe("1");
+    expect(JSON.stringify(JSON.rawJSON(1.1))).toBe("1.1");
+    expect(JSON.stringify(JSON.rawJSON(-1))).toBe("-1");
+    expect(JSON.stringify(JSON.rawJSON(-1.1))).toBe("-1.1");
+    expect(JSON.stringify(JSON.rawJSON(1.1e1))).toBe("11");
+    expect(JSON.stringify(JSON.rawJSON(1.1e-1))).toBe("0.11");
+    expect(JSON.stringify(JSON.rawJSON(null))).toBe("null");
+    expect(JSON.stringify(JSON.rawJSON(true))).toBe("true");
+    expect(JSON.stringify(JSON.rawJSON(false))).toBe("false");
+    expect(JSON.stringify(JSON.rawJSON('"foo"'))).toBe('"foo"');
+
+    expect(JSON.stringify({ 42: JSON.rawJSON(37) })).toBe('{"42":37}');
+    expect(JSON.stringify({ x: JSON.rawJSON(1), y: JSON.rawJSON(2) })).toBe('{"x":1,"y":2}');
+    expect(JSON.stringify({ x: { x: JSON.rawJSON(1), y: JSON.rawJSON(2) } })).toBe(
+        '{"x":{"x":1,"y":2}}'
+    );
+
+    expect(JSON.stringify([JSON.rawJSON(1), JSON.rawJSON(1.1)])).toBe("[1,1.1]");
+    expect(
+        JSON.stringify([
+            JSON.rawJSON('"1"'),
+            JSON.rawJSON(true),
+            JSON.rawJSON(null),
+            JSON.rawJSON(false),
+        ])
+    ).toBe('["1",true,null,false]');
+    expect(JSON.stringify([{ x: JSON.rawJSON(1), y: JSON.rawJSON(1) }])).toBe('[{"x":1,"y":1}]');
+});
+
+test("JSON.rawJSON error cases", () => {
+    expect(() => JSON.rawJSON(Symbol("123"))).toThrow(TypeError);
+    expect(() => JSON.rawJSON(undefined)).toThrow(SyntaxError);
+    expect(() => JSON.rawJSON({})).toThrow(SyntaxError);
+    expect(() => JSON.rawJSON([])).toThrow(SyntaxError);
+
+    const illegalChars = ["\n", "\t", "\r", " "];
+
+    illegalChars.forEach(char => {
+        expect(() => {
+            JSON.rawJSON(`${char}123`);
+        }).toThrow(SyntaxError);
+
+        expect(() => {
+            JSON.rawJSON(`123${char}`);
+        }).toThrow(SyntaxError);
+    });
+
+    expect(() => {
+        JSON.rawJSON("");
+    }).toThrow(SyntaxError);
+});