anchor.diff:    external String doSumUpTo2([String? a, String? b]);
     external String doSum1Or2NonNull(String a, [String b = 'bar']);
     external String doSumUpTo2NonNull([String a = 'foo', String b = 'bar']);
  +
  +  @JS('nameInJSMethod')
  +  external String nameInDartMethod(String a, String b);
  +  @JS('nameInJSGetter')
  +  external String get nameInDartGetter;
  +  @JS('nameInJSSetter')
  +  external set nameInDartSetter(String v);
  +  external String get nameInJSSetter;
   }
   
   void createClassTest() {
  
positive.code:   Expect.equals('foobar', foo.doSumUpTo2NonNull());
    Expect.equals('foobar', foo.doSumUpTo2NonNull('foo'));
    Expect.equals('foobar', foo.doSumUpTo2NonNull('foo', 'bar'));
  }
  
  @JS('JSClass.NestedJSClass')
  
negative.code:     globalThis.JSClass = function(foo) {
        this.foo = foo;
        this.nonNullableInt = 6;
        this.nameInJSGetter = 'foo';
        this.nonNullableIntReturnMethod = function() {
          return 7;
        }
  