I’m creating a simple class, but I get an error that I can’t understand. My class is very simple: But when I run in terminal with node script.js I always get an RangeError: Maximum call stack size exceeded error…. Where is the mistake? Thanks! Answer In ECMAScript (which defines JavaScript),…
Tag: constructor
Why declare/initialize a same property both inside and outside of constructor?
From Classes on mdn web docs: Public field declarations Aren’t the height and width outside of the constructor meaningless since they’re always overwritten in the constructor? What’s the significance of the height and width declaration/initialization outside of constructor in this case? Are …
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 …
How do i initialise an array of object in constructor in JavaScript
I would like to create a class with an array of object in the constructor. The idea is to create rects in a canvas with the values inside the objects. I have this array: I tried the following: Thanks for your help. Answer As already written, the addition of this works. See example with this.boxs
How to in React Component constructor set this state
I still learn much React JavaScript and now I can’t understand how to create this initial state. In the constructor here in the code I want to add to state by running this line: And direct after I want to add more state variables like this: The problem now is that state does not contain the first call t…
JavaScript instantiates class without usage React Native
I have the next problem/question in React Native: I have the next class, let’s say it A that looks like this: My A class in used in B class like this: And the makeApiRequest function from B class in used in App.js like this: And this makeRequest function is placed as an onPress action. My question is: A…
How to create a prototype for this type of constructor?
I explore the deep end of JavaScript. Well, let’s say I have a constructor function like this. Yes, I know this is a weird way of creating a constructor function, but … And I wanna add a prototype property like walk(), but it doesn’t work here. I know it looks stupid, but… QUESTION: Is…
Using method defined in the constructor after querying document from database
UPDATE ( ANOTHER SOLUTION) What I was looking for, I found out later, was the possibility of making the method static. Then I can apply the method independently from the class. Supposing I defined the following contructor: After fetching the User via CRUD operation (ex, findOne), I get an object back, the one…
What’s the purpose of using classes in React?
I mostly see JavaScript use classes as a constructor as following: What’s the reason React uses classes without using the contructor() function, such as following? I don’t see classes being used to create instances. Answer What’s the reason React uses classes without using the contructor() f…
XMLHttpRequest.onload constructor in Javascript?
When making a new XMLHttpRequest, like so There is a method (property ?) called onload. My question is, why we can assign a function to it? like this If onload is a property in XMLHttpRequest, the value of it will change when we assign a new value to it, like a function, right? What is the XMLHttpRequest.onlo…