Here are 20 commonly asked JavaScript interview questions, ranging from beginner to advanced levels:
πΉ Basic Level
What are the different data types present in JavaScript?
(e.g., String, Number, Boolean, Undefined, Null, Symbol, BigInt, Object)
What is the difference between var, let, and const?
What is hoisting in JavaScript?
What are truthy and falsy values in JavaScript?
What is the difference between == and ===?
What is a closure in JavaScript?
What is the difference between null and undefined?
What is an Immediately Invoked Function Expression (IIFE)?
Explain the concept of event bubbling and event delegation.
How does this keyword work in JavaScript?
πΉ** Intermediate Level**
What are arrow functions, and how are they different from regular functions?
What is the difference between synchronous and asynchronous code?
How do promises work in JavaScript?
What is the event loop in JavaScript?
What are JavaScript callbacks, and how do they differ from Promises?
What is the use of the bind(), call(), and apply() methods?
What are template literals? Provide an example.
How do you handle errors in JavaScript using try...catch?
πΉ** Advanced Level**
What are higher-order functions in JavaScript?
What are the differences between map(), filter(), and reduce()?