: DOM manipulation, event handling, and event delegation.
Promise.resolve() is encountered. Its .then() callback is placed directly into the . 'End' is printed immediately as it is a synchronous task.
| Module | Topics Covered | | :--- | :--- | | | JavaScript engine, client vs. server-side, variables ( var , let , const ), DOM, selectors, data types, operators, conditionals, loops, functions & arrow functions, arrays & objects, scope, hoisting, error handling, JSON, and asynchronous programming. | | 2. Variables & Datatypes | var , let , const , primitive vs. non-primitive types, null vs. undefined , typeof operator, and type coercion. | | 3. Operators & Conditions | Types of operators (unary, binary, ternary), short-circuit evaluation, operator precedence, conditional statements, == vs. === , and spread vs. rest operators. | | 4. Arrays | Creating arrays, adding/removing elements, indexOf() , find() vs. filter() , slice() , push() vs. concat() , pop() vs. shift() , splice() , map() vs. forEach() , sorting/reversing, destructuring, array-like objects, and conversion methods. | | 5. Loops | Loop types ( while , do-while , for ), break vs. continue , for...of vs. for...in , and comparison with forEach . | | 6. Functions | Named vs. anonymous functions, function expressions, arrow functions, callbacks, higher-order functions, parameters vs. arguments, default parameters, event handling, first-class functions, pure vs. impure functions, currying, and call/apply/bind methods. | | 7. Strings | String operations, immutability, concatenation methods, and string methods. | | 8. DOM (Document Object Model) | Accessing the DOM, selecting, modifying, creating, and removing elements, getElementById vs. querySelector , innerHTML vs. textContent , modifying style, and creating elements. | | 9. Error Handling | try...catch...finally , throw statement, error propagation, best practices, and types of errors. | | 10. Objects | Object creation, properties (adding, modifying, deleting), dot vs. bracket notation, iteration, checking for property existence, deep vs. shallow copy, Set and Map objects. | | 11. Events | Event types, Event Object, event delegation, event bubbling, capturing, event.preventDefault() , and the this keyword in events. | | 12. Closures | Lexical scoping, definition of a closure, benefits (encapsulation), limitations, and releasing closures from memory. | | 13-15. Asynchronous Programming | Sync vs. Async, setTimeout() , setInterval() , callbacks & callback hell, Promises ( .all() , .race() ), and Async/Await for error handling. | | 16. Browser APIs & Web Storage | window object, Web Storage API, local storage vs. session storage, cookies, and cross-cutting concerns. | | 17. Classes & OOP | Classes, constructors, the this keyword, and prototypal inheritance. | | 18. ECMAScript & Modules | ES6+ features (e.g., let / const , arrow functions, etc.), JS modules ( export , import ), static vs. dynamic imports, and module bundlers. | | 19. Security & Performance | eval() function, XSS & SQL Injection attacks, and best practices for security and performance. | | 20-22. Scenario & Coding | Tricky short questions, feature development (e.g., validation, pagination, drag-and-drop, search, chat), and coding challenges (string reversal, palindromes, anagrams, array operations, etc.). | happy rawat javascript interview questions pdf free upd
Happy Rawat is a well-known technical educator and content creator, highly regarded in the web development community for his practical, interview-focused JavaScript tutorials. His curated question sets specifically target the core mechanics and modern quirks of JavaScript that top-tier tech companies frequently test.
The output will be undefined , not a ReferenceError or 5 . Due to hoisting, the declaration var myVar is lifted to the top, but its assignment ( = 5 ) stays in place. The code is interpreted as: : DOM manipulation, event handling, and event delegation
Invokes the function immediately. It accepts the this context as the first argument, followed by an array (or array-like object) containing the arguments.
Focus on scope (functional vs. block), hoisting, and re-declaration. 'End' is printed immediately as it is a synchronous task
To effectively answer a question like "In what order will the numbers 1-4 be logged to the console?", you must understand the .
Master execution contexts, call stacks, scope chains, and closure mechanics.
Hoisting is a JavaScript behavior where variable and function declarations are moved to the top of their scope during the compilation phase. This means you can sometimes call a function before it's actually written in the code. 3. Prototypal Inheritance