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: function Parent(property) { …

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 …

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: let af = { MyClass: class { constructor() { console.log(“constructor of my class”); …

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 “type” as the original array, i.e. it has to be an instance of your class. .filter creates a new empty instance of your class: 1. Let O be ? ToObject(this value). […] 5. Let A be ? ArraySpeciesCreate(O, 0). […]