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Common JavaScript Interview Topics

Common JavaScript Interview Topics

  1. Core JavaScript Concepts

    • Variables (var, let, const)
    • Data types (string, number, boolean, object, array)
    • Operators (arithmetic, comparison, logical)
    • Control flow (if-else statements, switch statements, loops)

  2. Functions

    • Function declaration vs. function expression
    • Arrow functions
    • Scope and closures
    • Callback functions
    • Higher-order functions

  3. Object-Oriented Programming

    • Objects and prototypes
    • Constructors and classes
    • Inheritance and prototype chain
    • Encapsulation, abstraction, polymorphism

  4. Asynchronous JavaScript

    • Callbacks
    • Promises
    • async/await
    • Event loop

  5. DOM Manipulation

    • Selecting elements
    • Modifying elements
    • Creating and removing elements
    • Event handling

  6. Error Handling

    • Try-catch blocks
    • Error objects
    • Handling asynchronous errors

  7. Modules

    • CommonJS vs. ES6 modules
    • Module.exports and import/export syntax

  8. Browser APIs

    • Local storage
    • Fetch API
    • History API
    • Geolocation API

  9. ES6+ Features

    • Destructuring
    • Spread/rest operators
    • Template literals
    • Default parameters
    • Sets and Maps

  10. Testing

    • Unit testing with frameworks like Jest, Mocha, or Jasmine
    • Test runners like Karma
    • Testing libraries like Enzyme or React Testing Library

  11. Frameworks and Libraries

    • React.js
    • Angular
    • Vue.js
    • Express.js
    • Node.js

  12. Security

    • Cross-site scripting (XSS)
    • Cross-site request forgery (CSRF)
    • Content Security Policy (CSP)
    • Authentication and authorization

  13. Performance Optimization

    • Minification and bundling
    • Lazy loading
    • Debouncing and throttling
    • Code splitting

  14. Functional Programming

    • Immutability
    • Pure functions
    • Map, filter, reduce

  15. Data Structures and Algorithms

    • Arrays, stacks, queues, linked lists
    • Searching and sorting algorithms
    • Big O notation and algorithmic complexity