description('Tests for ES6 class syntax "extends"'); function shouldThrow(s, message) { var threw = false; try { eval(s); } catch(e) { threw = true; if (!message || e.toString() === eval(message)) testPassed(s + ":::" + e.toString()); else testFailed(s); } if (!threw) testFailed(s); } function shouldNotThrow(s) { var threw = false; try { eval(s); } catch(e) { threw = true; } if (threw) testFailed(s); else testPassed(s); } function shouldBe(a, b) { if (eval(a) === eval(b)) testPassed(a + ":::" + b); else testFailed(a + ":::" + b); } function shouldBeTrue(s) { if (eval(s) === true) testPassed(s); else testFailed(s); } class Base { constructor() { } baseMethod() { return 'base'; } overridenMethod() { return 'base'; } static staticBaseMethod() { return 'base'; } static staticOverridenMethod() { return 'base'; } } class Derived extends Base { constructor() { super(); } overridenMethod() { return 'derived'; } static staticOverridenMethod() { return 'derived'; } } shouldBeTrue('(new Base) instanceof Base'); shouldBe('Object.getPrototypeOf(new Base)', 'Base.prototype'); shouldBeTrue('(new Derived) instanceof Derived'); shouldBe('Object.getPrototypeOf(new Derived)', 'Derived.prototype'); shouldBe('Object.getPrototypeOf(Derived.prototype)', 'Base.prototype'); shouldBe('(new Derived).baseMethod()', '"base"'); shouldBe('(new Derived).overridenMethod()', '"derived"'); shouldBe('Derived.staticBaseMethod()', '"base"'); shouldBe('Derived.staticOverridenMethod()', '"derived"'); shouldThrow('x = class extends', '"SyntaxError: Unexpected end of script"'); shouldThrow('x = class extends', '"SyntaxError: Unexpected end of script"'); shouldThrow('x = class extends Base {', '"SyntaxError: Unexpected end of script"'); shouldNotThrow('x = class extends Base { }'); shouldNotThrow('x = class extends Base { constructor() { } }'); shouldBe('x.__proto__', 'Base'); shouldBe('Object.getPrototypeOf(x)', 'Base'); shouldBe('x.prototype.__proto__', 'Base.prototype'); shouldBe('Object.getPrototypeOf(x.prototype)', 'Base.prototype'); shouldBe('x = class extends null { constructor() { } }; x.__proto__', 'Function.prototype'); shouldBe('x.__proto__', 'Function.prototype'); shouldThrow('x = class extends 3 { constructor() { } }; x.__proto__', '"TypeError: The superclass is not a constructor."'); shouldThrow('x = class extends "abc" { constructor() { } }; x.__proto__', '"TypeError: The superclass is not a constructor."'); shouldNotThrow('baseWithBadPrototype = function () {}; baseWithBadPrototype.prototype = 3; new baseWithBadPrototype'); shouldThrow('x = class extends baseWithBadPrototype { constructor() { } }', '"TypeError: The value of the superclass\'s prototype property is not an object or null."'); shouldNotThrow('baseWithBadPrototype.prototype = "abc"'); shouldThrow('x = class extends baseWithBadPrototype { constructor() { } }', '"TypeError: The value of the superclass\'s prototype property is not an object or null."'); shouldNotThrow('baseWithBadPrototype.prototype = null; x = class extends baseWithBadPrototype { constructor() { } }'); shouldThrow('x = 1; c = class extends ++x { constructor() { } };'); shouldThrow('x = 1; c = class extends x++ { constructor() { } };'); shouldThrow('x = 1; c = class extends (++x) { constructor() { } };'); shouldThrow('x = 1; c = class extends (x++) { constructor() { } };'); shouldBe('x = 1; try { c = class extends (++x) { constructor() { } } } catch (e) { }; x', '2'); shouldBe('x = 1; try { c = class extends (x++) { constructor() { } } } catch (e) { }; x', '2'); shouldNotThrow('namespace = {}; namespace.A = class { }; namespace.B = class extends namespace.A { }'); shouldNotThrow('namespace = {}; namespace.A = class A { }; namespace.B = class B extends namespace.A { }'); shouldNotThrow('namespace = {}; namespace.A = class { constructor() { } }; namespace.B = class extends namespace.A { constructor() { } }'); shouldNotThrow('namespace = {}; namespace.A = class A { constructor() { } }; namespace.B = class B extends namespace.A { constructor() { } }'); shouldNotThrow('namespace = {}; namespace.A = class { constructor() { } }; namespace.B = class extends (namespace.A) { constructor() { } }'); shouldNotThrow('namespace = {}; namespace.A = class { constructor() { } }; namespace.B = class extends namespace["A"] { constructor() { } }'); shouldNotThrow('namespace = {}; namespace.A = class { constructor() { } }; function getClassA() { return namespace.A }; namespace.B = class extends getClassA() { constructor() { } }'); shouldNotThrow('namespace = {}; namespace.A = class { constructor() { } }; function getClass(prop) { return namespace[prop] }; namespace.B = class extends getClass("A") { constructor() { } }'); shouldNotThrow('namespace = {}; namespace.A = class { constructor() { } }; namespace.B = class extends (false||null||namespace.A) { constructor() { } }'); shouldThrow('namespace = {}; namespace.A = class { constructor() { } }; namespace.B = class extends false||null||namespace.A { constructor() { } }'); shouldNotThrow('x = 1; namespace = {}; namespace.A = class { constructor() { } }; namespace.B = class extends (x++, namespace.A) { constructor() { } };'); shouldThrow('x = 1; namespace = {}; namespace.A = class { constructor() { } }; namespace.B = class extends (namespace.A, x++) { constructor() { } };'); shouldThrow('namespace = {}; namespace.A = class { constructor() { } }; namespace.B = class extends new namespace.A { constructor() { } }'); shouldThrow('namespace = {}; namespace.A = class { constructor() { } }; namespace.B = class extends new namespace.A() { constructor() { } }'); shouldBe('x = 1; namespace = {}; namespace.A = class { constructor() { } }; try { namespace.B = class extends (x++, namespace.A) { constructor() { } } } catch (e) { } x', '2'); shouldBe('x = 1; namespace = {}; namespace.A = class { constructor() { } }; try { namespace.B = class extends (namespace.A, x++) { constructor() { } } } catch (e) { } x', '2'); shouldBe('Object.getPrototypeOf((class { constructor () { } }).prototype)', 'Object.prototype'); shouldBe('Object.getPrototypeOf((class extends null { constructor () { super(); } }).prototype)', 'null'); shouldThrow('new (class extends undefined { constructor () { this } })', '"TypeError: The superclass is not a constructor."'); shouldThrow('x = undefined; new (class extends x { constructor () { super(); } })', '"TypeError: The superclass is not a constructor."'); shouldBeTrue ('class x {}; new (class extends null { constructor () { return new x; } }) instanceof x'); shouldThrow('new (class extends null { constructor () { this; } })'); shouldThrow('new (class extends null { constructor () { super(); } })', '"TypeError: function is not a constructor (evaluating \'super()\')"'); shouldBe('x = {}; new (class extends null { constructor () { return x } })', 'x'); shouldThrow('y = 12; class C extends null { constructor () { return y; } }; new C;', '"TypeError: Cannot return a non-object type in the constructor of a derived class."'); shouldBeTrue ('class x {}; new (class extends null { constructor () { return new x; } }) instanceof x'); shouldBe('x = null; Object.getPrototypeOf((class extends x { }).prototype)', 'null'); shouldBeTrue('Object.prototype.isPrototypeOf(class { })'); shouldBeTrue('Function.prototype.isPrototypeOf(class { })'); var successfullyParsed = true;