Q521. What is an enum?
An enum is a type restricting variables to one value from a predefined set of constants. JavaScript has no enums but typescript provides built-in enum support. ```javascr...
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Q522. How do you list all properties of an object?
You can use the `Object.getOwnPropertyNames()` method which returns an array of all properties found directly in a given object. Let's see the usage of this in an example...
Q523. How do you get property descriptors of an object?
You can use the `Object.getOwnPropertyDescriptors()` method which returns all own property descriptors of a given object. The example usage of this method is below, ```ja...
Q524. What are the attributes provided by a property descriptor?
A property descriptor is a record which has the following attributes 1. `value`: The value associated with the property 2. `writable`: Determines whether the value associ...
Q525. How do you extend classes?
The `extends` keyword is used in class declarations/expressions to create a class which is a child of another class. It can be used to subclass custom classes as well as ...
Q526. How do I modify the url without reloading the page?
The `window.location.href` property will be helpful to modify the url but it reloads the page. HTML5 introduced the `history.pushState()` and `history.replaceState()` met...
Q527. How do you check whether or not an array includes a particular value?
The `Array#includes()` method is used to determine whether an array includes a particular value among its entries by returning either true or false. Let's see an example ...
Q528. How do you compare scalar arrays?
You can use length and every method of arrays to compare two scalars (compared directly using `===`) arrays. The combination of these expressions can give the expected re...
Q529. Can you have multiple useEffect hooks in a single component?
Yes, multiple useEffect hooks are allowed and recommended when you want to separate concerns. ```jsx useEffect(() => { // Handles API fetch }, []); useEffect(() => { // H...
Q530. How to get the value from get parameters?
The `new URL()` object accepts the url string and `searchParams` property of this object can be used to access the get parameters. ```javascript let urlString = "http://w...