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1. Top results related to javascript class

   • Class variable in javascript class

     Top Answer

     Answered Apr 20, 2009 · 5 votes

     The "only" way to do what you want to do is to use a function as the "class". This way you are declaring a "class" whose public "static" members can be accessed. Something like this:

     function MyObject() { // constructor stuff here}MyObject.EVENT_NAME = "event_name";console.log(MyObject.EVENT_NAME); // No need to instantiate MyObject

     However, seems to me like you are mixing concepts from statically typed languages with Javascript's more dynamic stuff. Why would you want to access a member of an object that has not been created?

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     1/5

   • javascript class inherit from Function class

     Top Answer

     Answered Nov 03, 2011 · 14 votes

     Your trying to inherit from Function. This is a right pain to do. I suggest you do the following instead

     Live Example

     var Proto = Object.create(Function.prototype);Object.extend(Proto, { constructor: function (d) { console.log("construct, argument : ", d); this.d = d; // this is your constructor logic }, call: function () { console.log("call", this.d); // this get's called when you invoke the "function" that is the instance return "from call"; }, method: function () { console.log("method"); // some method return "return from method"; }, // some attr attr: 42});

     You want to create a prototype object that forms the basis of your "class". It has your generic methods/attributes. It also has a constructor that gets invoked on object construction and a call method that gets invoked when you call the function

     var functionFactory = function (proto) { return function () { var f = function () { return f.call.apply(f, arguments); }; Object.keys(proto).forEach(function (key) { f[key] = proto[key]; }); f.constructor.apply(f, arguments); return f; }}

     A function factory takes a prototype object and returns a factory for it. The returned function when called will give you a new function object that "inherits" from your prototype object.

     var protoFactory = functionFactory(proto);var instance = protoFactory();-

     Here you create your factory and then create your instance.

     However this isn't proper prototypical OO. we are just shallow copying properties of a prototype into a new object. So changes to the prototype will not reflect back to the original object.

     If you want real prototypical OO then you need to use a hack.

     var f = function () { // your logic here};f.__proto__ = Proto;

     Notice how we use the non-standard deprecated .__proto__ and we are mutating the value of [[Prototype]] at run-time which is considered evil.

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     2/5

   • JavaScript: Class.method vs. Class.prototype.method

     Top Answer

     Answered Oct 28, 2009 · 738 votes

     Yes, the first function has no relationship with an object instance of that constructor function, you can consider it like a 'static method'.

     In JavaScript functions are first-class objects, that means you can treat them just like any object, in this case, you are only adding a property to the function object.

     The second function, as you are extending the constructor function prototype, it will be available to all the object instances created with the new

     keyword, and the context within that function (the this

     keyword) will refer to the actual object instance where you call it.

     Consider this example:

     // constructor functionfunction MyClass () { var privateVariable; // private member only available within the constructor fn this.privilegedMethod = function () { // it can access private members //.. };}// A 'static method', it's just like a normal function // it has no relation with any 'MyClass' object instanceMyClass.staticMethod = function () {};MyClass.prototype.publicMethod = function () { // the 'this' keyword refers to the object instance // you can access only 'privileged' and 'public' members};var myObj = new MyClass(); // new object instancemyObj.publicMethod();MyClass.staticMethod();

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     3/5

   • JavaScript Class extends Keyword

     Example

     Create a class named "Model" which will inherit the methods from the "Car" class:

     class Car { constructor(brand) { this.carname = brand; } present() { return 'I have a ' + this.carname; }}class ModelextendsCar { constructor(brand, mod) { super(brand); this.model = mod; } show() { return this.present() + ', it is a ' + this.model; }}mycar = new Model("Ford", "Mustang");document.getElementById("demo").innerHTML = mycar.show();

     Try it Yourself »

     Description

     The extends keyword is used to create a child class of another class (parent).

     The child class inherits all the methods from another class.

     Inheritance is useful for code reusability: reuse properties and methods of an existing class when...

     Check all answers on W3Schools

     4/5

   • Also try

     javascript class constructor	javascript class variables
     javascript class w3schools	javascript class inheritance
     javascript class example	javascript class methods
     javascript class tutorial	javascript class properties

     5/5

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2. developer.mozilla.org › en-US › docsClasses - JavaScript | MDN - MDN Web Docs

   developer.mozilla.org › en-US › docs

   • Cached

   Mar 10, 2024 · Classes are a template for creating objects. They encapsulate data with code to work on that data. Classes in JS are built on prototypes but also have some syntax and semantics that are unique to classes. For more examples and explanations, see the Using classes guide.

3. www.w3schools.com › Js › js_classesJavaScript Classes - W3Schools

   www.w3schools.com › Js › js_classes

   • Cached

   JavaScript Classes are templates for JavaScript Objects. JavaScript Class Syntax. Use the keyword class to create a class. Always add a method named constructor(): Syntax. class ClassName { constructor () { ... } Example. class Car { constructor (name, year) { this.name = name; this.year = year; } The example above creates a class named "Car".

4. developer.mozilla.org › en-US › docsUsing classes - JavaScript | MDN - MDN Web Docs

   developer.mozilla.org › en-US › docs

   • Cached

   In JavaScript, classes are mainly an abstraction over the existing prototypical inheritance mechanism — all patterns are convertible to prototype-based inheritance. Classes themselves are normal JavaScript values as well, and have their own prototype chains.

5. javascript.info › classClass basic syntax - The Modern JavaScript Tutorial

   javascript.info › class

   • Cached

   Dec 16, 2021 · In object-oriented programming, a class is an extensible program-code-template for creating objects, providing initial values for state (member variables) and implementations of behavior (member functions or methods). In practice, we often need to create many objects of the same kind, like users, or goods or whatever.

6. developer.mozilla.org › en-US › docsClasses in JavaScript - Learn web development | MDN

   developer.mozilla.org › en-US › docs

   • Cached

   Jan 1, 2024 · In this article, we've gone through the main tools available in JavaScript for writing object-oriented programs. We haven't covered everything here, but this should be enough to get you started. Our article on Classes is a good place to learn more.

7. www.javascripttutorial.net › javascript-classJavaScript Class Fundamentals: Introduction to ES6 Class

   www.javascripttutorial.net › javascript-class

   • Cached

   A JavaScript class is a blueprint for creating objects. A class encapsulates data and functions that manipulate data. Unlike other programming languages such as Java and C#, JavaScript classes are syntactic sugar over the prototypal inheritance. In other words, ES6 classes are just special functions.

8. javascript.info › classesClasses - The Modern JavaScript Tutorial

   javascript.info › classes

   • Cached

   Class basic syntax. Class inheritance. Static properties and methods. Private and protected properties and methods. Extending built-in classes. Class checking: "instanceof".

9. web.dev › learn › javascriptClasses | web.dev

   web.dev › learn › javascript

   • Cached

   Mar 31, 2024 · Learn. JavaScript. Classes. ES6 introduced the concept of "classes" in JavaScript, which differs from classes in other programming languages. Here, classes are special functions that serve as templates for creating objects that already contain data, properties associated with that data, and methods related to the manipulation of that data.

10. devdoc.net › en-US › docsClasses - JavaScript | MDN

    devdoc.net › en-US › docs

    • Cached

    Jul 26, 2017 · JavaScript classes provide a much simpler and clearer syntax to create objects and deal with inheritance. Defining classes. Classes are in fact "special functions ", and just as you can define function expressions and function declarations, the class syntax has two components: class expressions and class declarations. Class declarations.

11. www.freecodecamp.org › news › javascript-classes-how-they-work-with-use-caseJavaScript Classes – How They Work with Use Case Example

    www.freecodecamp.org › news › javascript-classes-how-they-work-with-use-case

    • Cached

    Dec 13, 2021 · So in this guide, you will learn about classes in JavaScript, inheritence, abstract functions, how to use keywords such as super and extends, static keywords, and private members of classes. Let's dive in.