2025

What is the difference between function scope and block scope?

August 16, 2025

1. Function Scope 2. Block Scope ✅ Key Differences Feature Function Scope Block Scope Keyword var let, const Visibility Accessible...

Explain private variables in JavaScript.

August 16, 2025

In JavaScript, a private variable is a variable that is not accessible directly from outside the object/class where it is...

What is the difference between call, apply, and bind?

August 16, 2025

these three (call, apply, and bind) are JavaScript function methods that let you explicitly set the value of this when...

What are rest parameters and default parameters?

August 16, 2025

1. Rest Parameters (...) ✅ Example: 🔹 Here, numbers becomes an array of all passed arguments. Key Points: 2. Default...

What is the arguments object in JavaScript?

August 16, 2025

In JavaScript, the arguments object is an array-like object that is automatically available inside every non-arrow function. It contains all...

What is the difference between function declarations and function expressions?

August 16, 2025

1. Function Declaration ✅ Example: 2. Function Expression ✅ Example: 3. Key Differences Feature Function Declaration Function Expression Hoisting Fully...

Explain IIFE (Immediately Invoked Function Expression).

August 16, 2025

An IIFE (Immediately Invoked Function Expression) is a JavaScript function that is defined and executed immediately after its creation. It...

What is a callback function?

August 16, 2025

A callback function is a function that is passed as an argument to another function, and then executed later (called...

What are first-class functions?

August 16, 2025

In programming, first-class functions (also called first-class citizens) mean that functions are treated like any other value. In languages that...

What is the difference between typeof and instanceof?

August 16, 2025

The difference between typeof and instanceof in JavaScript is subtle but very important. Let’s break it down clearly: 1. typeof...