JavaScript Interview Questions

What is JavaScript?
What is the difference between var, let, and const?
What are data types in JavaScript?
What is type coercion?
What is the difference between == and ===?
What is a closure in JavaScript?
What is a callback function?
What is the difference between null and undefined?
What is the use of the typeof operator?
What is hoisting in JavaScript?
What is the difference between function declaration and function expression?
What is an arrow function?
What is the scope of a variable?
What is lexical scope?
What is the difference between global and local scope?
What is an object in JavaScript?
What is an array in JavaScript?
What are array methods like push, pop, shift, unshift?
What is the map() method?
What is the filter() method?
What is the reduce() method?
What is an event in JavaScript?
What is event bubbling?
What is event delegation?
What is the DOM?
What is the use of querySelector?
What is the difference between innerText and innerHTML?
How to create and append elements using JavaScript?
What is a promise in JavaScript?
What is async and await?
What is the use of setTimeout and setInterval?
What is JSON?
How to convert JSON to object and vice versa?
What is destructuring?
What is spread operator?
What is rest parameter?
What are template literals?
What is NaN in JavaScript?
What is isNaN function?
What is the difference between for, forEach, and for...of loops?
What is the difference between var hoisting and let/const hoisting?
What is a JavaScript class?
How to create objects using a class?
What is inheritance in JavaScript?
What is the prototype in JavaScript?
What is prototypal inheritance?
What is the difference between call, apply, and bind?
What is the this keyword?
What is strict mode?
What is a symbol in JavaScript?
What are the different ways to clone an object?
What is shallow copy vs deep copy?
What is the difference between Array and Object?
What is event loop in JavaScript?
What is the call stack?
What is the microtask and macrotask queue?
What are higher-order functions?
What is currying?
What is memoization?
What is debounce and throttle?
What is localStorage?
What is sessionStorage?
What is cookies in JavaScript?
What is difference between localStorage and sessionStorage?
How to handle errors in JavaScript?
What is try, catch, and finally?
What is throw in JavaScript?
What is the use of debugger statement?
What are ES6 features?
What is module in JavaScript?
What is import and export?
What is the use of default export?
What are promises and how they work?
How to handle promise chaining?
What is fetch API?
What is async/await and how it improves code readability?
What is callback hell?
How to avoid callback hell?
What is a generator function?
What is the yield keyword?
What is the difference between synchronous and asynchronous code?
What are JavaScript engines?
What is the difference between client-side and server-side JavaScript?
What is Node.js?
What is npm?
What is event-driven programming?
What is the difference between stack and heap?
What is garbage collection?
What are the types of errors in JavaScript?
How to debug JavaScript code?
What are breakpoints?
What is a Web API?
What is CORS?
What is the difference between GET and POST requests?
How to make an API call using fetch?
What is destructuring in function parameters?
What is default parameter value?
What is the use of includes() method in arrays?
What is the difference between slice and splice?
What is the difference between Math.floor(), Math.ceil(), and Math.round()?