JSTests/stress/reflect-get-prototype-of.js

function shouldBe(actual, expected) {
    if (actual !== expected)
        throw new Error('bad value: ' + actual);
}

function shouldThrow(func, message) {
    var error = null;
    try {
        func();
    } catch (e) {
        error = e;
    }
    if (!error)
        throw new Error("not thrown.");
    if (String(error) !== message)
        throw new Error("bad error: " + String(error));
}

shouldBe(Reflect.getPrototypeOf.length, 1);

shouldThrow(() => {
    Reflect.getPrototypeOf("hello");
}, `TypeError: Reflect.getPrototypeOf requires the first argument be an object`);

var object = { hello: 42 };
shouldBe(Reflect.getPrototypeOf(object), Object.prototype);
shouldBe(Reflect.getPrototypeOf(Reflect.getPrototypeOf(object)), null);
var proto = [];
object.__proto__ = proto;
shouldBe(Reflect.getPrototypeOf(object), proto);

var array = [];
shouldBe(Reflect.getPrototypeOf(array), Array.prototype);
var proto = [];
array.__proto__ = Object.prototype;
shouldBe(Reflect.getPrototypeOf(array), Object.prototype);

class Base {
}

class Derived extends Base {
}

shouldBe(Reflect.getPrototypeOf(new Derived), Derived.prototype);
shouldBe(Reflect.getPrototypeOf(Reflect.getPrototypeOf(new Derived)), Base.prototype);
shouldBe(Reflect.getPrototypeOf(Reflect.getPrototypeOf(Reflect.getPrototypeOf(new Derived))), Object.prototype);
shouldBe(Reflect.getPrototypeOf(Reflect.getPrototypeOf(Reflect.getPrototypeOf(Reflect.getPrototypeOf(new Derived)))), null);

var object = Object.create(null);
shouldBe(Reflect.getPrototypeOf(object), null);