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I am using 'this' keyword for a long time. But when someone asks me to explain it, I am confused that how to explain it. I know that I can use this in a method of class to access any variable and method of the same class. class MyClass{ function MyMethod1(){ echo "Hello World"; } function MyMethod2(){ $this->MyMethod1(); } } Is it a object of a class that we don't need to initialise and can be used only within the class or anything else. How to explain? Thanks A class is a mold for an object: it specifies how the object looks like (variables) and what it can do (functions). If you instanciate

I'm writing a linked list and I want a struct's destructor (a Node struct) to simply delete itself, and not have any side effects. I want my list's destructor to iteratively call the Node destructor on itself (storing the next node temporarily), like this: //my list class has first and last pointers //and my nodes each have a pointer to the previous and next //node DoublyLinkedList::~DoublyLinkedList { Node *temp = first(); while (temp->next() != NULL) { delete temp; temp = temp->next(); } } So this would be my Node destructor: Node::~Node { delete this; } Is this acceptable, especially in

I'm trying to call a function with the "onclick" event as so: <td id="A1" onclick="move()" class="white"></td> <td id="A2" onclick="move()" class="painted bp"></td> <td id="A3" onclick="move()" class="white"></td> In the function itself, i refer to "this": function move(e){ var myId = this.id; alert("myId"); } When I run the whole thing, the alert says 'undefined'. When I try alert(this) I get [object window]. I'm working with IE9, btw. Thanks Shadow Wizard When calling a function from an event handler, its this isn't set by the handler (though you can pass this from the handler per Xdazz's

I'm trying to generalize my hack from an answer to another question . It should provide a way to reference a value which is not constructed yet inside its initializer (of course, not directly, but in lambdas and object expressions). What I have at the moment: class SelfReference<T>(val initializer: SelfReference<T>.() -> T) { val self: T by lazy { inner ?: throw IllegalStateException("Do not use `self` until initialized.") } private val inner = initializer() } fun <T> selfReference(initializer: SelfReference<T>.() -> T): T { return SelfReference(initializer).self } It works, see this example:

I have the following ES6 code using a fat arrow function: var test = { firstname: 'David', fn: function() { return ['one', 'two', 'tree'].map(() => this.firstname) } } console.log(test.fn()) According to how arrow functions are supposed to work I'd expect this to be the test object. ES6Fiddle , Traceur and Firefox produce the expected output which is ["David", "David", "David"] . When enabling those features in Chrome using chrome://flags/#enable-javascript-harmony , however, I get [undefined, undefined, undefined] . If you console.log(this) it shows that it is the window object and you get an

I get confused on a JavaScript this reference situation. I am working on a code that I declare function inside an object method. (The reason is to tidy up code inside an object method, while keeping the functions private to the method.) The following is an experiment to re-produce my problem. I found that the this inside greeting function refers to the window scope instead of person scope. var person = { nickname: "Makzan", sayHi: function() { console.log(this); var greeting = function() { console.log(this); return "Aloha " + this.nickname; } console.log(greeting()); } } person.sayHi(); (same

In the following construct: (function(){ var x = function(){ alert('hi!'); } var y = function(){ alert("hi again!"); } this.show = function(){ alert("This is show function!"); } })(); Why does this refer to window object? Should everything inside IIFE be isolated from global scope? Are x and y functions also properties of window global object? Also, even if I use put var h = ... at the beginning: var h = (function(){ var x = function(){ alert('hi!'); } var y = function(){ alert("hi again!"); } this.show = function(){ alert("This is show function!"); } })(); this still refers to window object -

I have the following code. I expected to see "archive" object on my firebug console, but I see Window object. Is it normal? var archive = function(){} archive.prototype.action = { test: function(callback){ callback(); }, test2: function(){ console.log(this); } } var oArchive = new archive(); oArchive.action.test(oArchive.action.test2); oArchive.action.test2 gets you a reference to a function that callback then points to, but that function is then called using callback() , which means it is not called as a method and hence this is the global object. The key point is that this is not bound to a