60_reflect_get_prototype_of.js

// 60: Reflect - getPrototypeOf
// To do: make all tests pass, leave the assert lines unchanged!

describe('`Reflect.getPrototypeOf` returns the prototype', function() {

  it('works like `Object.getPrototypeOf`', function() {
    const viaObject = Object.getPrototypeOf({});
    const viaReflect = Reflect.getPrototypeOf({});

    assert.strictEqual(viaObject, viaReflect);
  });

  it('throws a TypeError for a non-object', function() {
    let fn = () => { Reflect.getPrototypeOf(1) };
    assert.throws(fn, TypeError);
  });

  it('a `new Set()` has a prototype', function() {
    const aSet = new Set;

    assert.equal(Reflect.getPrototypeOf(aSet), Set.prototype);
  });

  it('for a class, it is `Klass.prototype`', function() {
    class Klass {}
    const proto = Reflect.getPrototypeOf(new Klass());

    assert.equal(proto, Klass.prototype);
  });

  it('for a old-style class, works too', function() {
    function Klass() {}
    const proto = Reflect.getPrototypeOf(new Klass());

    assert.equal(proto, Klass.prototype);
  });

  it('an array has a prototype too', function() {
    let arr = [];
    const expectedProto = Array.prototype;

    assert.equal(Reflect.getPrototypeOf(arr), expectedProto);
  });

  // TODO
  // it('getting the prototype of an "exotic namespace object" returns `null`', function() {
  //   http://www.ecma-international.org/ecma-262/6.0/#sec-module-namespace-exotic-objects-getprototypeof
  //   Don't know how to write a test for this yet, without creating a dep in tddbin hardcoded
  //   PRs welcome
  //   assert.equal(Reflect.getPrototypeOf(namespace exotic object), null);
  // });
});