The grouping operator does not destroy property references, which are provoking the method call. This is explicitly mentioned in the spec: NOTE: This algorithm does not apply GetValue to the result of evaluating Expression. The principal motivation for this is so that operators such as delete and typeof may be applied to parenthesised expressions. In … Read more
From this quirksmode article with regard to attachEvent: Events always bubble, no capturing possibility. The event handling function is referenced, not copied, so the this keyword always refers to the window and is completely useless. The result of these two weaknesses is that when an event bubbles up it is impossible to know which HTML … Read more
This is not jQuery’s fault, it is integral to the way JavaScript handles objects. Unlike in most other object-oriented languages, ‘this’ is not bound on a per-method level in JavaScript; instead, it’s determined purely by how the function is called: Bob= { toString: function() { return ‘Bob!’; }, foo: function() { alert(this); } }; Brian= … Read more
You really have a nice corner case there! My take on it: the first is straightforward. Just a standard call. The ‘.’ operator lets you call the function setting b as the execution context. the second is exactly the same thing: the parens are entirely optional and the interpreter is treating the expression inside it … Read more
It depends on how a function is called. If a function is not referenced through being an attribute of an object (e.g. refToMethod) then it will be assigned the “Global context” which is window. However, when a function is an attribute of object (e.g. obj.method), we refer to it as a method, and it is … Read more
LocalScreen.this refers to this of the enclosing class. This example should explain it: public class LocalScreen { public void method() { new Runnable() { public void run() { // Prints “An anonymous Runnable” System.out.println(this.toString()); // Prints “A LocalScreen object” System.out.println(LocalScreen.this.toString()); // Won’t compile! ‘this’ is a Runnable! onMake(this); // Compiles! Refers to enclosing object onMake(LocalScreen.this); … Read more
If this is undefined within an arrow function, it’s undefined outside of the arrow as well. Arrow function simply capture the this of the surrounding scope. In this case, you’re declaring myOutsideFunction as a method on an object literal and never binding it or doing anything else that would call it with the object as … Read more
The end of a constructor is a special place in terms of concurrency, with respect to final fields. From section 17.5 of the Java Language Specification: An object is considered to be completely initialized when its constructor finishes. A thread that can only see a reference to an object after that object has been completely … Read more
Inside of your anonymous function this is the global object. Inside of test, this is the instance of MyObject on which the method was invoked. Whenever you call a function like this: somceFunction(); // called function invocation this is always the global object, or undefined in strict mode (unless someFunction was created with bind** — … Read more
I’m trying to pass display.draw which is the function in which webkitRequestAnimationFram resides. webkitRequestAnimationFrame will presumably call the function you pass in, something like this: function webkitRequestAnimationFrame(callback) { // stuff… callback(); // other stuff… } At this point, you have dissociated (detached) the draw function from its invocation context. You need to bind the function … Read more