description('Tests for the descriptors of the properties implicitly defined by ES6 class syntax'); function descriptor(object, propertyName) { return Object.getOwnPropertyDescriptor(object, propertyName); } function enumeratedProperties(object) { var properties = []; for (var propertyName in object) properties.push(propertyName); return properties; } shouldBeFalse('class A {}; descriptor(A, "prototype").writable'); shouldBe('class A {}; var x = A.prototype; A.prototype = 3; A.prototype', 'x'); shouldBeFalse('class A {}; descriptor(A, "prototype").enumerable'); shouldBeTrue('class A {}; A.foo = "foo"; enumeratedProperties(A).includes("foo")'); shouldBeFalse('class A {}; enumeratedProperties(A).includes("prototype")'); shouldBeFalse('class A {}; descriptor(A, "prototype").configurable'); shouldThrow('class A {}; Object.defineProperty(A, "prototype", {value: "foo"})', '"TypeError: Attempting to change value of a readonly property."'); shouldBeTrue('class A { static foo() {} }; descriptor(A, "foo").writable'); shouldBe('class A { static foo() {} }; A.foo = 3; A.foo', '3'); shouldBeFalse('class A { static foo() {} }; descriptor(A, "foo").enumerable'); shouldBeFalse('class A { static foo() {} }; enumeratedProperties(A).includes("foo")'); shouldBeTrue('class A { static foo() {} }; descriptor(A, "foo").configurable'); shouldBe('class A { static foo() {} }; Object.defineProperty(A, "foo", {value: "bar"}); A.foo', '"bar"'); shouldBe('class A { static get foo() {} }; descriptor(A, "foo").writable', 'undefined'); shouldBe('class A { static get foo() { return 5; } }; A.foo = 3; A.foo', '5'); shouldBeFalse('class A { static get foo() {} }; descriptor(A, "foo").enumerable'); shouldBeFalse('class A { static get foo() {} }; enumeratedProperties(A).includes("foo")'); shouldBeFalse('class A { static get foo() {} }; enumeratedProperties(new A).includes("foo")'); shouldBeTrue('class A { static get foo() {} }; descriptor(A, "foo").configurable'); shouldBe('class A { static get foo() {} }; Object.defineProperty(A, "foo", {value: "bar"}); A.foo', '"bar"'); shouldBeTrue('class A { foo() {} }; descriptor(A.prototype, "foo").writable'); shouldBe('class A { foo() {} }; A.prototype.foo = 3; A.prototype.foo', '3'); shouldBeFalse('class A { foo() {} }; descriptor(A.prototype, "foo").enumerable'); shouldBeFalse('class A { foo() {} }; enumeratedProperties(A.prototype).includes("foo")'); shouldBeFalse('class A { foo() {} }; enumeratedProperties(new A).includes("foo")'); shouldBeTrue('class A { foo() {} }; descriptor(A.prototype, "foo").configurable'); shouldBe('class A { foo() {} }; Object.defineProperty(A.prototype, "foo", {value: "bar"}); A.prototype.foo', '"bar"'); shouldBe('class A { get foo() {} }; descriptor(A.prototype, "foo").writable', 'undefined'); shouldBe('class A { get foo() { return 5; } }; A.prototype.foo = 3; A.prototype.foo', '5'); shouldBeFalse('class A { get foo() {} }; descriptor(A.prototype, "foo").enumerable'); shouldBeFalse('class A { get foo() {} }; enumeratedProperties(A.prototype).includes("foo")'); shouldBeFalse('class A { get foo() {} }; enumeratedProperties(new A).includes("foo")'); shouldBeTrue('class A { get foo() {} }; descriptor(A.prototype, "foo").configurable'); shouldBe('class A { get foo() {} }; Object.defineProperty(A.prototype, "foo", {value: "bar"}); A.prototype.foo', '"bar"'); shouldBeTrue('class A { }; descriptor(A.prototype, "constructor").writable'); shouldBe('class A { }; A.prototype.constructor = 3; A.prototype.constructor', '3'); shouldBeTrue('class A { }; x = {}; A.prototype.constructor = function () { return x; }; (new A) instanceof A'); shouldBeFalse('class A { }; descriptor(A.prototype, "constructor").enumerable'); shouldBeFalse('class A { }; enumeratedProperties(A.prototype).includes("constructor")'); shouldBeFalse('class A { }; enumeratedProperties(new A).includes("constructor")'); shouldBeTrue('class A { }; descriptor(A.prototype, "constructor").configurable'); shouldBe('class A { }; Object.defineProperty(A.prototype, "constructor", {value: "bar"}); A.prototype.constructor', '"bar"'); var successfullyParsed = true;