A typical JavaScript/Frontend interview is composed of 4 to 5 rounds.

• JavaScript-related problem solving
• DataStructures and Algorithms
• Machine-Coding round
• Web fundamentals
• Frontend system design

This is a curated list of solved problems in JavaScript categorized on the type & nature of the problem which you can refer to and use as a cheat sheet for interview preparation.

It contains Data Structures & Algorithms, functions, async, closure, promises, hoisting, & other JavaScript-core concepts problems.

You can also checkout my youtube playlist where I am solving one question daily for 100 days that can help you to prepare and crack your JavaScript interview.

JavaScript concepts revision

• ES6 Intro
• Babel
• let vs var in javascript
• Template Strings
• Function & this in JavaScript
• Javascript Fat Arrow Function
• Functions with default parameters in javascript
• What are Pure and Impure functions in JavaScript
• ES6 Object Literals
• Javascript set
• Javascript Map
• Javascript Spread and Rest Operator
• Javascript destructuring
• Introduction to es6 class
• ES6 Modules
• Javascript Symbol
• Javascript Iterator
• Understanding closure in JavaScript
• Understanding powerful Array.reduce() method

DataStructures

• Javascript array: Complete reference.
• Javascript Objects: Complete Reference.
• Javascript String: Complete Reference.
• Implement Stack data structure in javascript.
• Queue data structure in javascript.
• List data structure in javascript.
• Linked list data structure in javascript.
• Implement stack using linked list.
• Implement queue using linked list.
• Doubly linked list implementation in javascript.
• Implement deque data structure in javascript.
• Deque data structure with doubly linked list.
• Circular linked list implementation in javascript.
• Circular Doubly linked list in javascript.
• Priority Queue Implementation in javascript.
• Tree data structure in javascript.
• Heap data structure in Javascript.
• Treap data structure in Javascript.
• Trie data structure in Javascript.
• Javascript graph data structure.
• AVL Tree in Javascript.

Algorithms

It contains only the important ones, you can check out the whole list here.

• Implement Stack data structure in javascript.
• Print all subarrays with a given sum k in an array.
• Program to check if a subarray with 0 sum exits or not.
• Find distinct ways to climb the stairs in javascript.
• Caesar Cipher in javascript.
• Count all substrings having character k.
• Number of subarrays with given sum k.
• Implement a Stack using Queue.
• Implement queue using two stack.
• Learn how to implement two stack with an array.
• Alternatively merge two different arrays.
• Implement stack with max and min function.
• Merge two sorted linked list.
• How to find loop in linked list.
• Find height and width of binary tree.
• Tree traversal in Javascript.
• Flood fill algorithm in javascript.
• Find longest palindrome in a string.
• Find all anagrams substring in a string.
• Find the largest sum of contiguous subarray.
• Check if binary tree has path sum.
• Rotate matrix 90 degrees clockwise and anti-clockwise.
• Find the intersection point of two linked list.
• Trapping rain water in javascript.
• Diagonal traversal of binary tree.
• Check if binary tree is symmetric.
• Find floor and ceil of binary search tree.
• Find Least Common Ancestor (LCA) of binary tree.
• Find kth smallest and largest element in BST.
• Serialize and Deserialize Binary Tree.
• Find inorder successor of a given key in a BST.
• Find inorder predecessor of a given key in a BST.
• N meetings in one room.
• knapsack problem in Javascript (Bounded & Unbounded).
• LRU cache in Javascript.
• Fractional knapsack problem.
• Longest Common Subsequence.
• Longest repeated subsequence.
• Longest Consecutive Sequence.
• Deepest leaves sum of binary tree.

Sorting

• Selection sort in javascript.
• Dutch national flag problem.
• Bubble sort algorithm in javascript.
• Recursive Bubble sort algorithm.
• Insertion sort algorithm in javascript.
• Recursive Insertion Sort Algorithm.
• Sorting a linked list.
• Bubble sort using two stacks.
• Merge sort in javascript.
• Iterative merge sort algorithm.
• Merge sort a linked list.
• Quick sort algorithm in Javascript.
• Quick sort Iterative.
• Quick sort using linked list.
• Heap sort algorithm in Javascript.
• Iterative heap sort in Javascript.
• Counting Sort Algorithm In Javascript.
• Radix sort algorithm in Javascript.
• Bucket Sort Algorithm.
• Shell Sort Algorithm In Javascript.

Searching

• Linear search algorithm in javascript.
• Binary search in javascript.
• Iterative binary search in javascript.
• Search in a sorted rotated array.

JavaScript specific problems

I am currently working on this list, these are a few random questions, you can find the full list here.

• Implement mapLimit async function
• Execute async functions in parallel in JavaScript
• HTML encoding of a string
• Implement an in-memory search engine
• Highlight the words in the string
• Throttle an array of task
• Circuit breaker in JavaScript
• Get different value of Object property in JavaScript
• Create analytics SDK in JavaScript
• Fetch with Timeout in JavaScript
• Debouncing with leading and trailing options
• Cached api call with expiry time
• Piping function in JavaScript – Part 2
• Aggregate the Input values
• Handle race condition in React
• Run useEffect() hook only on update in React
• Set object value at the string path
• Get object value from string path
• Create custom cookie in JavaScript
• Piping function in JavaScript – Part 1
• Fetch request and response interceptor
• Make high priority Api call in JavaScript
• Aggregate array of objects on the given keys
• Filter array of objects on value or index
• Currying – part 4
• Currying – part 3
• Implement browser history in JavaScript
• Method chaining in JavaScript – Part 2
• Method chaining in JavaScript – Part 1
• Implement getByClassNameHierarchy() function in JavaScript
• Array with event listeners in JavaScript
• CSS selector generator
• Localstorage with expiry
• Array iterator method in JavaScript
• Convert JSON to HTML
• Find element with the given color property
• Get object value from the string path
• Share data between two browser window with JavaScript
• Piping function in JavaScript – Part 1
• How to merge objects in javascript.
• Compare two array or object with JavaScript.
• What is debouncing in javascript?.
• What is throttling in javascript?.
• Number increment counter in Javascript (React).
• Detect idle state (inactive) in Javascript.
• Deep flatten object in Javascript – 1.
• Currying in JavaScript.
• Capture product visible on viewport when user stops scrolling.
• Animate elements in a sequence.
• Create Pausable auto incrementer.
• Implement clearAllTimeout in JavaScript.
• Implement ClearAllInterval in JavaScript.
• Singleton design pattern in JavaScript.
• Observer design pattern in JavaScript.
• Remove cycle from the object in JavaScript.
• Execute async functions in Series.
• Retry promises N number of times in JavaScript.
• In-memory filesystem library in JavaScript.

JavaScript projects (Machine-Coding)

• Create simple calculator with javascript.
• Whack a mole game in javascript.
• Rock, Paper, Scissor, Lizard, Spock game in javascript.
• Eye follow cursor in javascript.
• Text typing effect in javascript.
• Word falling effect in javascript.
• Day night toggle switch in javascript.
• User profile viewer in javascript.
• Roman to numeral converter javascript.
• Tic tac toe game in javascript with bot.
• Create website walkthrough assistant in JavaScript
• Chrome Extension to use ChatGPT anywhere

React questions (Machine coding)

• Create a lightbox (modal-image-gallery) in Reactjs
• Create responsive slideshow gallery in Reactjs
• Responsive slideshow in Reactjs
• Search with pagination in Reactjs
• Editable todo-list in React
• Multi-Stepper component in React
• Implement Feature Flag component in React
• useCopy() hook in React
• Implement Infinite Scroll in React
• Switch-Case component in React
• useToggle() hook in React
• useHasFocus() hook in React
• useOnClickOutside() hook in React
• Two-step login form in React
• useScript() hook in React
• useOnScreen() hook in React
• useWhyDidYouUpdate() hook in react
• useThrottle() hook in React
• useResponsive() hook in React
• useDebounce() hook in React
• useAsync() hook in React
• useIdle() hook in React
• usePrevious() hook in React.
• Create scrollspy in react
• Image comparison slider in react
• Create loader component in react
• Typing effect component in react
• Create tooltip in react
• Create scroll indicator in react
• Create timeline in react
• React image zoom
• React drag and drop list of elements
• Create slider in react
• Login form component in react
• Lazy loading component in react.
• Create voice visualizer in react
• Create modal component in react
• Create alert box in react
• Create tabs in react
• Sliding sidebar menu with hamburger in react
• Create autocomplete search in react
• Create dropdown in react
• Create accordion in react
• Pagination component in react
• Create progress bar in react
• Toggle switch in react
• Create select dropdown in react
• Create file uploader in react
• Create checkbox group component in react
• Create radio group component in react
• Create checkbox in react
• Create input component in react
• Create custom button component in react

Web fundamentals

• Testing Strategies: Ensuring Quality in Software Engineering
• How a web page is rendered in browser?
• Anatomy of URL
• The frontend Landscape – Different Architectures
• Reactivity in JavaScript frameworks
• Tree shaking in JavaScript and how it helps
• Load websites faster with Code Splitting
• Monorepo vs Polyrepo in frontend
• Data Normalization of Frontend State
• Static site generation (SSG) vs Incremental Static regeneration (ISR)
• Single-Page Application (CSR) vs Multi-Page Application (SSR)
• Authenication on the web and its best practices
• Understanding the Cross-Site scripting (XSS) attacks
• Decoding and preventing the Cross-Site forgery (CSRF) attacks
• Understanding the Cross-Site scripting (XSS) attacks

Frontend System Design

• What is System Design in Software Engineering?
• What to expect in Frontend System Design?
• Design the video streaming web app like Netflix, Youtube, Prime videos.
• Design a trello / kanban board
• Design a food ordering web app like Swiggy, Zomato, Uber eats
• Design collaborative text editor
• Design an form enricher, shortner SDK
• Design news feed of Facebook, Twitter, Linkedin
• Design a configurable frontend application with different login type
• Design the frontend of the group or suite of apps
• Design the frontend of the Pinterest or Google photos
• Design the frontend of the Instagram

Design patterns

• Builder design pattern in JavaScript
• Iterator design pattern in JavaScript
• Container and Presentational pattern in React
• Prototype design pattern in JavaScript
• Higher-order component pattern in React
• Provider design pattern for Reactjs
• Proxy design pattern in JavaScript
• Observer design pattern in JavaScript
• Singleton design pattern in JavaScript

Interview Experience

• Frontend Interview Process at Atlassian
• Frontend Interview Process at Coursera
• Razorpay frontend interview experience
• Fullstack interview experience at Nutanix
• OLA-SDE2-Frontend Interview Experience
• Dream11 – SDE2 – Frontend Interview Experience
• Reliance JIO interview experience

More questions will be added to it as and when I write them.

All the very best!.