In the following code : The user Object is the prototype of admin Object, As we see line (**) sets the fullName for admin Object, although user Object remains the way it was. So is it correct to say that user Properties & Methods are copied to admin Object ? Answer Using Object.getOwnPropertyNames reveals that by using admin.fullName = “Alice
Tag: inheritance
Different behavior when extend natives class with constructor and passing arguments to super
Different behavior calling a constructor and without calling it, when creating an instance of an inherited class: 1Case when I pass constructor: 2Case when it happens automatically There are different behavior Please tell me what is the difference, and why is this behavior observed? Answer In a subclass, the default constructor the JavaScript engine will supply if you don’t provide
JavaScript – Confusion between global classes and inheritance
Total begginer who learns JS here. I don’t understand why when you declare a variable it doesn’t TOTALLY inherit of it’s parent class methods, for e.g.: Why don’t the variables inherit of all of the methods of it’s parent classes? Instead of that you need to mix between the fonctions of Array and myArr. They should be identitical on the
Javascript functions, multiple prototype inheritance
I have an assignment to implement a diagram using javascript prototypes and constructors. For now I have to implement multiple inheritance using prototypes. I know how to implement single inheritance and I am stuck on inheriting multiple prototypes. This question is focusing on WeatherData inheriting Event and DataType objects. I havent tested the code but I am sure it’s wrong
concatenative inheritance two methods with same signature
The code below prints only the event contents, how do I make that print WheatherData.value number? I am coming from java and I am used to do it this way. Answer The line above causing the problem. When you assign _event object to { getValue, toString } object you are simply overriding toString method of WeatherData function. Instead, just return
Subclassing in TypeScript and using more specific properties or methods
In TypeScript, how can I get a more specific subclass of a more generic class to allow referencing more specific properties and methods of that subclass when parent classes define them further up the inheritance tree? To explain my question, I think this code sums up what I’m trying to achieve: Note the type error above. A Car must have
Javascript prototype inheritance and “instanceof”
I just cannot understand, why in object inheritance “instanceof” fails to evaluate “children”-objects as instances of parent prototypes. For example: As for inheritance of classes (or rather of what is deemed to be classes in JS), the situation is different: What is the cause of this difference? Is it possible to create children-objects so that they were correctly recognised as
Javascript – How do I have a get/set in a method? (e.g. pineapple.is_a.fruit)
I have an assignment where I’m supposed to make magic out of programming. I’m unable to find any answers online, as I do not know the search term for it (tried method in a method etc…). Appreciate any help given! Here’s what I got: I need to create a class that builds upon itself. e.g. I do not even know
Uncaught TypeError: class heritage this.MyClass is not an object or null
I’m trying to extend one class from another inside the module. The code looks like that: in the result console throws the TypeError: Uncaught TypeError: class heritage this.MyClass is not an object or null referring to line *. Could you help me to fix that? Answer this is only set when you’re calling a method of the object, it’s not
JS Array.prototype.filter with Array extending class constructor call
I have a Array extending class A which I want to filter. It seems like the constructor gets called another time with just 0 as parameter. Why is that? Here is an example showing the problem: Which logs: Where is the 0 comming from? Answer Array.prototype.filter is returning a new (array) value. That value needs to be of the same