Top 5 Most Asked JavaScript Interview Questions Every Developer Should Know

JavaScript is one of the most important programming languages in modern web development. Whether you are preparing for frontend, backend, or full-stack roles, interviewers frequently test your understanding of core JavaScript concepts. In this post on DEV Community, we will explore the top 5 most commonly asked JavaScript interview questions with simple explanations and examples. ✅ 1. What is Closure in JavaScript? ✔ Answer: A closure is created when a function remembers and can access variables from its outer function even after the outer function has finished execution. Closures help in: Data privacy Maintaining state Creating function factories Example: function outer() { let count = 0; return function inner() { count++; console.log(count); }; } const counter = outer(); counter(); counter(); ✔ Explanation: The inner function remembers the count variable even after the outer function is executed. This is called a closure. ✅ 2. What is the Difference Between var, let, and const? ✔ Ans