Tests for ES6 class syntax declarations On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". PASS constructorCallCount is 0 PASS A.someStaticMethod() is staticMethodValue PASS A.someStaticGetter is getterValue PASS setterValue = undefined; A.someStaticSetter = 123; setterValue is 123 PASS (new A).someInstanceMethod() is instanceMethodValue PASS constructorCallCount is 1 PASS (new A).someGetter is getterValue PASS constructorCallCount is 2 PASS (new A).someGetter is getterValue PASS setterValue = undefined; (new A).someSetter = 789; setterValue is 789 PASS (new A).__proto__ is A.prototype PASS A.prototype.constructor is A PASS class threw exception SyntaxError: Unexpected end of input. PASS class [ threw exception SyntaxError: Unexpected token [. PASS class { threw exception SyntaxError: Unexpected token {. PASS class X { threw exception SyntaxError: Unexpected end of input. PASS class X { ( } threw exception SyntaxError: Unexpected token (. PASS class X {} did not throw exception. PASS class X { constructor() {} constructor() {} } threw exception SyntaxError: A class may only have one constructor. PASS class X { get constructor() {} } threw exception SyntaxError: Class constructor may not be an accessor. PASS class X { set constructor() {} } threw exception SyntaxError: Class constructor may not be an accessor. PASS class X { constructor() {} static constructor() { return staticMethodValue; } } did not throw exception. PASS class X { constructor() {} static constructor() { return staticMethodValue; } }; X.constructor() is staticMethodValue PASS class X { constructor() {} static prototype() {} } threw exception SyntaxError: Classes may not have static property named prototype. PASS class X { constructor() {} static get prototype() {} } threw exception SyntaxError: Classes may not have static property named prototype. PASS class X { constructor() {} static set prototype() {} } threw exception SyntaxError: Classes may not have static property named prototype. PASS class X { constructor() {} prototype() { return instanceMethodValue; } } did not throw exception. PASS class X { constructor() {} prototype() { return instanceMethodValue; } }; (new X).prototype() is instanceMethodValue PASS class X { constructor() {} set foo(a) {} } did not throw exception. FAIL class X { constructor() {} set foo({x, y}) {} } should not throw exception. Threw exception SyntaxError: Unexpected token {. PASS class X { constructor() {} set foo() {} } threw exception SyntaxError: Setter must have exactly one formal parameter.. PASS class X { constructor() {} set foo(a, b) {} } threw exception SyntaxError: Setter must have exactly one formal parameter.. PASS class X { constructor() {} get foo() {} } did not throw exception. PASS class X { constructor() {} get foo(x) {} } threw exception SyntaxError: Getter must not have any formal parameters.. PASS class X { constructor() {} get foo({x, y}) {} } threw exception SyntaxError: Unexpected token {. PASS successfullyParsed is true TEST COMPLETE