JavaScript Interview Preparation

This repository is a comprehensive resource for JavaScript interview and placement preparation. It covers all core concepts, practical coding problems, and advanced topics, with clear explanations and code samples. Each file is focused on a specific topic or set of questions commonly asked in technical interviews.

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File Structure & Topic Guide

• 01-variables-and-data-types.js
  Covers variable declarations (var, let, const), data types, and scoping rules.
  Explanation:

  • var is function-scoped, while let and const are block-scoped.
  • const cannot be reassigned.
  • JavaScript has dynamic types: String, Number, Boolean, Null, Undefined, Symbol, Object.
    MDN: var, let, const

• 02-functions.js
  Shows function declarations, expressions, arrow functions, default/rest parameters.
  Explanation:

  • Functions can be declared in multiple ways.
  • Arrow functions do not have their own this.
  • Rest parameters allow variable number of arguments.
    MDN: Functions

• 03-arrays-and-methods.js
  Demonstrates array creation and methods like map, filter, reduce, forEach, find.
  Explanation:

  • map creates a new array by transforming each element.
  • filter creates a new array with elements that pass a test.
  • reduce accumulates array values into a single result.
    MDN: Array methods

• 04-objects.js
  Object creation, property access, destructuring, cloning, and methods.
  Explanation:

  • Objects store key-value pairs.
  • Destructuring extracts properties into variables.
  • Spread operator (...) can clone objects.
    MDN: Objects

• 05-es6-features.js
  ES6+ features: template literals, destructuring, spread/rest, modules.
  Explanation:

  • Template literals use backticks for string interpolation.
  • Destructuring simplifies extracting values from arrays/objects.
  • Modules allow code organization and reuse.
    MDN: ES6 features

• 06-asynchronous.js
  Callbacks, Promises, async/await.
  Explanation:

  • Callbacks are functions passed as arguments.
  • Promises represent future values.
  • async/await simplifies asynchronous code.
    MDN: Promises

• 07-dom-manipulation.js
  DOM selection, events, and content manipulation (for browser environment).
  Explanation:

  • Use getElementById, querySelector to select elements.
  • Add event listeners for interactivity.
  • Change content/styles dynamically.
    MDN: DOM

• 08-advanced-topics.js
  Closures, hoisting, scope, prototypes, inheritance, this keyword.
  Explanation:

  • Closures allow functions to access outer variables.
  • Hoisting moves declarations to the top of scope.
  • Prototypes enable inheritance.
  • this refers to the calling context.
    MDN: Closures
    MDN: this

• 09-coding-practice.js
  Common coding problems: reverse string, largest number, palindrome, FizzBuzz.
  Explanation:

  • Practice problems to test logic and array/string manipulation.
    LeetCode JavaScript Problems

• 10-coding-practice-2.js
  More coding problems: second largest, remove duplicates, count vowels, merge arrays, anagrams, etc.
  Explanation:

  • Covers a variety of array and string manipulation tasks.
    InterviewBit JavaScript Questions

• 10-coding-practice-webdev.js
  Practical web development tasks: DOM events, fetch API, debounce, localStorage, etc.
  Explanation:

  • Real-world tasks for frontend interviews.
    MDN: Web APIs

• 11-js-concept-questions.js
  Conceptual questions: var/let/const, async functions, function types, map/reduce, cloning, scope.
  Explanation:

  • Deep dive into language fundamentals and ES6+ features.

• 12-js-concept-questions-2.js
  More concept questions: closures, hoisting, deep copy, destructuring, arrow functions, unique values, etc.

• 13-js-concept-questions-3.js
  Array/object manipulation: copy, deep copy, compare, intersection, flatten, remove, merge, etc.

• 14-js-difference-questions.js
  Difference-based questions: null vs undefined, == vs ===, function types, arrow vs regular, map vs forEach, call/apply/bind, shallow vs deep copy, sync vs async, localStorage vs sessionStorage.

• 15-js-concept-questions-4.js
  More array/object practice: difference, chunk, count, swap, remove property, check empty, merge, random, capitalize, flatten, etc.

• 16-js-most-asked-interview-questions.js
  Most frequently asked coding problems: reverse string, palindrome, max in array, FizzBuzz, remove duplicates, factorial, missing number, anagrams, count vowels, intersection.

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How to Use

1. Clone or download this repository.
2. Open files in your code editor (e.g., VS Code).
3. Run .js files using Node.js (except 07-dom-manipulation.js, which is for browser console).
4. Read explanations and experiment with the code.
5. Use the reference links for deeper understanding.

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Recommended Learning Resources

• MDN JavaScript Guide
• JavaScript.info
• Eloquent JavaScript (free book)
• Frontend Interview Handbook
• LeetCode JavaScript Problems

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Follow me for such more upcoming placement prepration

• Linkedin : https://www.linkedin.com/in/satyam-prajapati-13a690256/

• Twitter : https://x.com/Satyam9352

• Thank you

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