Yes you only need $() when you’re using jQuery. If you want jQuery’s help to do DOM things just keep this in mind. $(this)[0] === this Basically every time you get a set of elements back jQuery turns it into a jQuery object. If you know you only have one result, it’s going to be … Read more
getApplicationContext() is almost always wrong. Ms. Hackborn (among others) have been very explicit that you only use getApplicationContext() when you know why you are using getApplicationContext() and only when you need to use getApplicationContext(). To be blunt, “some programmers” use getApplicationContext() (or getBaseContext(), to a lesser extent) because their Java experience is limited. They implement … Read more
this refers to the current object. Each non-static method runs in the context of an object. So if you have a class like this: public class MyThisTest { private int a; public MyThisTest() { this(42); // calls the other constructor } public MyThisTest(int a) { this.a = a; // assigns the value of the parameter … Read more
“How does this and $scope work in AngularJS controllers?” Short answer: this When the controller constructor function is called, this is the controller. When a function defined on a $scope object is called, this is the “scope in effect when the function was called”. This may (or may not!) be the $scope that the function … Read more
Arrow functions capture the this value of the enclosing context function Person(){ this.age = 0; setInterval(() => { this.age++; // |this| properly refers to the person object }, 1000); } var p = new Person(); So, to directly answer your question, this inside your arrow function would have the same value as it did right … Read more
JavaScript has no classes class-based object model. It uses the mightier prototypical inheritance, which can mimic classes, but is not suited well for it. Everything is an object, and objects [can] inherit from other objects. A constructor is just a function that assigns properties to newly created objects. The object (created by a call with … Read more
The examples have very different outcomes. Before looking at the differences, the following should be noted: A constructor’s prototype provides a way to share methods and values among instances via the instance’s private [[Prototype]] property. A function’s this is set by how the function is called or by the use of bind (not discussed here). … Read more
this is a keyword in JavaScript that is a property of an execution context. Its main use is in functions and constructors. The rules for this are quite simple (if you stick to best practices). Technical description of this in the specification The ECMAScript standard defines this via the abstract operation (abbreviated AO) ResolveThisBinding: The … Read more
What you should know about this this (aka “the context”) is a special keyword inside each function and its value only depends on how the function was called, not how/when/where it was defined. It is not affected by lexical scopes like other variables (except for arrow functions, see below). Here are some examples: function foo() … Read more
You aren’t assigning a function and an object to the same variable you are redefining the what the symbol foo is bound to. Everytime you set foo = you are binding what is on the right hand side to that symbol. You can’t use this to access the function because it is a different object. … Read more