Tests for calling the constructors of ES6 classes On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". PASS new A did not throw exception. PASS A() threw exception TypeError: Class constructors cannot be invoked without 'new'. PASS new B did not throw exception. PASS B() threw exception TypeError: Class constructors cannot be invoked without 'new'. PASS new (class { constructor() {} })() did not throw exception. PASS (class { constructor() {} })() threw exception TypeError: Class constructors cannot be invoked without 'new'. PASS new (class extends null { constructor() { super() } })() threw exception TypeError: function () {} is not a constructor. PASS (class extends null { constructor() { super() } })() threw exception TypeError: Class constructors cannot be invoked without 'new'. PASS successfullyParsed is true TEST COMPLETE