closures

In Swift you can create a function for a button like this: button.addTarget(self, action: #selector(buttonAction), forControlEvents: .TouchUpInside) However is there a way I can do something like this: button.whenButtonIsClicked({Insert code here}) That way I do not even have too declare an explicit function for the button. I know I can use button tags but I would prefer to do this instead. Create your own UIButton subclass to do this: class MyButton: UIButton { var action: (() -> Void)? func whenButtonIsClicked(action: @escaping () -> Void) { self.action = action self.addTarget(self, action:

This is basically a followup question to this: Can't pass event to addEventListener: closure issue . I have read almost every related question and can't find the answer to this. The function below is executed within a loop where the parameters are pulled from an array of data. With this function I am able to pass different/new parameters to each instance of an event listener. The outerfunction allows for the values of the parameters to be encapsulated within closure so that the actual values are available, not just references to the holders. Additionally, the passeventfunction passes the event

I want to do this in Javascript: function Z( f ) { f(); } function A() { this.b = function() { Z( function () { this.c() } ); } this.c = function() { alert('hello world!'); } } var foo = new A(); foo.b(); It can be accomplished this way: function Z( f ) { f(); } function A() { var self = this; this.b = function() { Z( function () { self.c() } ); } this.c = function() { alert('hello world!'); } } var foo = new A(); foo.b(); Is there a better way? Keeping a reference to the parent (like you have) is a good approach, however for your specific example there's no need for the anonymous wrapper, you

This question already has an answer here: How do JavaScript closures work? 86 answers How can one understand closures in Javascript? In general terms, a closure is a function bound to one or more external variables. When it is called, the function is able to access these variables. In JavaScript, closures are often implemented when functions are declared inside another function. The inner function accesses variables of the parent one, even after the parent function has terminated In this statement, "a closure is a function bound to one or more external variables", does it mean we can do this :

Given the following (heavily edited, pseudo-)code: int count = 0; thing.Stub(m => m.AddBlah()).WhenCalled(o => count++); thing.Stub(m => m.RemoveBlah()).WhenCalled(o => count--); DoStuff(thing); Assert.AreEqual(1, count); ReSharper provides a warning on count - "Access to modified closure". I understand why I'm getting this warning (the count variable is being modified in two different lambdas, and is likely to have undesirable semantics), but I don't understand ReSharper's advice: "Wrap local variable in array". If I let ReSharper do this, I get: int count[] = { 0 }; thing.Stub(m => m.AddBlah