Q2541. What is Lexical Scope?
Lexical scope is the ability for a function scope to access variables from the parent scope. ```js function x(){ var a=10; function y(){ console.log(a); // will print a ,...
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Q2542. How to detect system dark mode in javascript?
The combination of `Window.matchMedia()` utility method along with media query is used to check if the user has selected a dark color scheme in their operating system set...
Q2543. What is the purpose of requestAnimationFrame method?
The requestAnimationFrame() method in JavaScript is used to schedule a function to be called before the next repaint of the browser window, allowing you to create smooth,...
Q2544. What is the difference between substring and substr methods?
Both `substring` and `substr` are used to extract parts of a string, but there are subtle differences between the substring() and substr() methods in terms of **syntax** ...
Q2545. How to find the number of parameters expected by a function?
The function's object has a **length** property which tells you how many formal parameters expected by a function. This is a static value defined by the function, not the...
Q2546. What is globalThis, and what is the importance of it?
Nowadays JavaScript language is used in a wide variety of environments and each environment has its own object model. Due to this fact, there are different ways(syntax) t...
Q2547. What are the array mutation methods?
JavaScript array methods can be categorized into two groups: 1. Mutating methods: These are the methods that directly modify the original array. 1. Non-mutating methods: ...
Q2548. What is module scope in JavaScript?
Module scope is a feature introduced with ES6 (ES2015) modules that creates a scope specific to a module file, isolating variables and functions declared within it from t...
Q2549. What are shadowing and illegal shadowing?
Both **shadowing** and **illegal shadowing** refer to how variable names can "hide" or override others within nested scopes. **Shadowing** occurs when a variable declared...
Q2550. Why is it important to remove event listeners after use?
In JavaScript, you need to be mindful of removing event listeners to avoid memory leaks — especially in long-lived apps like single-page applications (SPAs) or when worki...