How can I see a Javascript object's prototype chain?

Given the following code: function a() {} function b() {} b.prototype = new a(); var b1 = new b(); We can stay that a has been added to b's prototype chain. Great. And, all the following are...

Does JavaScript have classes?

A friend and I had an argument last week. He stated there were no such things as classes in JavaScript. I said there was as you can say var object = new Object() He says "as there is no word class...

Benefits of prototypal inheritance over classical?

So I finally stopped dragging my feet all these years and decided to learn JavaScript "properly". One of the most head-scratching elements of the languages design is it's implementation of...

Confusing JavaScript statement: "var x = new this();"

I thought I understood the concept of the JavaScript prototype object, as well as [[proto]] until I saw a few posts regarding class inheritance. Firstly, "JavaScript OOP - the smart way" at...

Javascript prototype operator performance: saves memory, but is it faster?

I read here (Douglas Crockford) using prototype operator to add methods to Javascript classes saves also memory. Then I read in this John Resig's article *"Instantiating a function with a bunch of...

Abstract methods in Python

I am having trouble in using inheritance with Python. While the concept seems too easy for me in Java yet up till now I have been unable to understand in Python which is surprising to me at...

Multiple inheritance/prototypes in JavaScript

I've come to a point where I need to have some sort of rudimentary multiple inheritance happening in JavaScript. (I'm not here to discuss whether this is a good idea or not, so please kindly keep...

Node.js / Express.js - How to override/intercept res.render function?

I'm building a Node.js app with Connect/Express.js and I want to intercept the res.render(view, option) function to run some code before forwarding it on to the original render...

__proto__ VS. prototype in JavaScript

This figure again shows that every object has a prototype. Constructor function Foo also has its own __proto__ which is Function.prototype, and which in turn also references via its __proto__...

Difference between Node object and Element object?

I am totally confused between Node object and Element object. document.getElementById() returns Element object while document.getElementsByClassName() returns NodeList object(Collection of...

What are the benefits to using anonymous functions instead of named functions for callbacks and parameters in JavaScript event code?

I'm new-ish to JavaScript. I understand many of the concepts of the language, I've been reading up on the prototype inheritance model, and I'm whetting my whistle with more and more interactive...

Prototyping in Javascript

In prototypal languages object can basically clone each other. So, lets say we have a constructor function: Bla = function() { this.a = 1; } I can create a new instance of that object like...

Copy prototype for inheritance?

I was playing around with JavaScript in particular simulating object oriented programming with classes and whatnot. I knew about this way of achieving inheritance MyClass.prototype = new...

How to check inheritance (object/prototype of)

I have want to check if an object extends another object (true, false): Example: var BaseObject = function(object) { this.name = object.name; this.someFunction = object.someFunction; ...

Why use Object.prototype.hasOwnProperty.call(myObj, prop) instead of myObj.hasOwnProperty(prop)?

If I understand correctly, each and every object in JavaScript inherits from the Object prototype, which means that each and every object in JavaScript has access to the hasOwnProperty function...

Why is extending native objects a bad practice?

Every JS opinion leader says that extending the native objects is a bad practice. But why? Do we get a perfomance hit? Do they fear that somebody does it "the wrong way", and adds enumerable types...

How to prototype a duplicate prototype method for Array in javascript

I'm trying to implement a duplicate method to the js Array prototype which concats a duplicate of the array to itself like so: [11,22,3,34,5,26,7,8,9].duplicate(); //...

How add new method in response and request

I want to add new method in response and request of node.js. How i can do it more efficiently? I can't understand how this is done in express.js

classical inheritance vs prototypal inheritance in javascript

I have googled so many links and can't get good idea about the difference between classical inheritance and prototypal inheritance? I have learned some things from these but I'm still confused...

Illegal Invocation on addEventListener

With jQuery you can use .on()/.off()/.trigger() methods on any jQuery object, giving you powerful access to the event system. I'm trying to do something similar in vanilla JavaScript but I keep...

AngularJS : ng-if | Hidden(Removed) ng-model variable not removed from $scope

I am trying to understand the working of ng-if in contrast with ng-show. After reading the docs and going through the related stackoverflow question here, I understand that ng-if removes the DOM...

dequeueReusableCellWithIdentifier returns nil

I am using a Storyboard's prototype UITableViewCell and getting nil when dequeueReusableCellWithIdentifier is called in cellForRowAtIndexPath. I have triple checked that the Xcode's Identifier...

Douglas Crockford on Class Free OOP in JavaScript

Douglas Crockford has a really good talk on "The Better Parts" of ES6. Among other things, he encourages a move away from prototypal inheritance in favor of class free OOP. Here he says he stopped...

What benefits does ES2015 (ES6) `class` syntax provide?

I have many question about ES6 classes. What's the benefit of using class syntax? I read that public/private/static will be part of ES7, is that a reason? Moreover, is class a different kind of...

Convert javascript class instance to plain object preserving methods

I want to convert an instance class to plain object, without losing methods and/or inherited properties. So for example: class Human { height: number; weight: number; constructor()...

Why setter/getter definition in .assign object merge doesn't work?

I am trying to implement a sort of inheritance in my JS app. Here is what I have: function FooObject(param1, param2) { this._param1= param1; this._param2=...

Does Object.keys(anObject) return anObject's prototype?

I'm reading Eloquent JavaScript's Map section and I'm having trouble understanding its last paragraph: If you do have a plain object that you need to treat as a map for some reason, it is useful...

Difference between Object.create(Parent.prototype) vs Object.create(Parent) during prototype inheritance

In typical JavaScript inheritance, we pass the Parent.prototype to Object.create. function Parent() {}; function Child() { Parent.call(this); } Child.prototype =...

Detect fetch API request on web page in JavaScript

Background: I am working with the Shopify ScriptTag which allows me to add a JavaScript file on the storefront. All I have is that script file. Current Behaviour: There is an option, "Buy It Now",...

Object.hasOwn() vs Object.prototype.hasOwnProperty()

The new method Object.hasOwn() returns a boolean indicating whether the specified object has the indicated property as its own property but so does Object.prototype.hasOwnProperty(), what is the...