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JavaScript Interview Guide Book
120 Solved JavaScript Interview Questions
JavaScript Practice Playground
Data Structures
Stack
Queue
Objects: complete reference
List
Linked list
Stack using linked list
Queue using linked list
Doubly linked list
Deque data structure
Deque data structure with Doubly linked list
Circular linked list
Priority Queue
Circular Doubly linked list
Tree
Heap
Treap
Trie
Graph
AVL Tree
Algorithms
2 sum
3 sum
4 sum
Print all the quadruplets with given sum
Convert decimal to binary, octal or hexa
Count number of sub-string occurrence in a string
Swap two numbers without temp variables
Palindrome string
Check balanced parentheses
Find the biggest perfect square in an array
Print all subarrays with a given sum k in an array
Find digital root of a given number
Buggy Calculator
Form the smallest possible number from the given number
Find missing alphabets to make a string panagram
Difference between square of sum of numbers and sum of square of numbers.
Converting string to jadencase
Check if given number is armstrong in javascript
Find all the armstrong number between two numbers
Print matrix in zigzag format
Print matrix in L pattern
Program to check the prime number
Find the largest prime factor
Find factorial of a number
Convert Roman numeral to an integer
Print all the unique 2 digit combinations of given numbers
Program to find the nth Fibonacci in javascript
Program to print the Collatz sequence
Maximum Collatz sequence under 1000000
Check if an array is palindrome
Sort a stack using another stack
Check if string contains a substring
Algorithm to check if a subarray with 0 sum exits or not.
Find the correct position to insert an element in the array
Check if two string are anagram of each other
Minimum characters to delete to make string anagram
Find the maximum sum of products of two arrays.
Program to add two binary numbers
Find distinct ways to climb the stairs
Program to reverse a queue
Reverse a stack using recursion
Caesar Cipher
Program to find the GCD of two numbers
Find the LCM of two numbers
FizzBuzz program
Program to find leap year
Program to print all the prime numbers from 1 to 100
Count all substrings having character k
Number of subarrays with given sum k
Reverse a string using recursion
Reverse a string using stack
Reverse an array
Absolute difference between diagonals of matrix
Program to print the chess board pattern
Program to print the pyramid pattern
Program to print the diamond pattern
Program to print the floyd triangle
Program to print the pascal triangle patterns
Program to print all the permutation of string
Algorithm to merge two sorted array
Implement a Stack using Queue
How to use array sort in javascript
Selection sort
Dutch national flag problem
Bubble sort
Recursive Bubble sort
Bubble sort using two stacks
Insertion sort
Recursive Insertion Sort
Sorting a linked list
Sort string based frequency of characters
Merge sort
Iterative merge sort
Merge sort a linked list
Quick sort
Quick sort Iterative
Quick sort using linked list
Counting Sort
Radix sort
Bucket Sort
Shell Sort
Heap sort
Iterative heap sort
Sort a string ignoring the case
Find the maximum depth of nested parentheses in a string
Implement two stack with an array
Reverse a linked list
Reverse a linked list recursively
Program to reverse a linked list using a stack
Program to check if two stacks are equal
Program to print the next greater element in the array
Program to check palindrome linked list
Program to find the duplicate element in the linked list
Program to find an element in array such that sum of left array is equal to sum of right array
Alternatively merge two different arrays
Sum and Product of all the nodes in the linked list which are less than k
Print the last k nodes of the linked list in reverse
Decode a string (encoded with number followed by string)
Program to sort only positive numbers of the array
Count number of sub string recursively
Implement stack with max and min function
Shuffle an array
Reverse a doubly linked list
Recursively reverse a doubly linked list
Merge two sorted linked list
Find loop in linked list
Implement queue using two stack
Find non duplicate number in an array
Check if two strings are equal with # backspace characters
Find least frequent number from an array
Find the most frequent element in an array
Find the element with k frequency in an array
Linear search algorithm
Binary search
Iterative binary search
Find first or last occurrence of a given number in a sorted array
Search in a sorted rotated array
Median of two sorted arrays
Tree traversal
Find height and width of binary tree
Flatten binary tree to linked list
Check if binary tree has path sum
Check if binary tree is symmetric
Check if given binary tree is full.
Print right view of a binary tree
Print the left view of a binary tree
Top view of a binary tree
Bottom view of a binary tree
Diagonal traversal of binary tree
Invert a binary tree | Recursive and Iterative solutions
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
Deepest leaves sum of binary tree
Reverse a sublist of linked list
Add two numbers represented by linked lists
Print the last k nodes of the linked list in reverse.
Find the intersection point of two linked list
Flood fill algorithm
Find longest palindrome in a string
Find the element that appears once in sorted array
Find all anagrams substring in a string
Sort string based frequency of characters
Find largest subarray with equal numbers of 0’s and 1’s
Reverse last k elements in a queue
Find the largest sum of contiguous subarray
Find numbers that appear twice in an array
Find number of trailing zeros in factorial
Rotate matrix 90 degrees clockwise and anti-clockwise
Set matrix zeroes
Next permutation problem
Trapping rain water
Maximum consecutive one’s in a binary array
Maximum consecutive one’s or zero’s in a circular array
Find all unique paths in a grid
Find square of a number without using *, / and pow()
Combination sum problem
Find all binary strings that can be formed from wildcard pattern
Word Break Problem
Find the longest common prefix
Reverse words in a string
Convert string to integer (ATOI)
Merge overlapping intervals
N meetings in one room
knapsack problem in Javascript (Bounded & Unbounded)
Fractional knapsack problem
LRU cache
Longest Common Subsequence
Longest common subsequence | Print all LCS
Longest repeated subsequence
Longest Consecutive Sequence
Valid Palindrome II
3Sum closest
JavaScript problem practice
Publisher-subscriber 1
Publisher-subscriber 2
Proxy object
Implement an in-memory search engine
Fetch with timeout
Cached api call with expiry time
Piping function - 1
Piping function - 2
Retry promises N number of times
Memoize a function
Method chaining - 1
Method chaining - 2
Execute async functions in Series
CSS selector generator
Implement circuit breaker
Curry - 1
Curry - 2
Curry - 3
Curry - 4
HTML encoding of a string - 1
HTML encoding of a string - 2
Get object value from string path
Set object value at the string path
Create custom cookie
Fetch request and response interceptor
Aggregate array of objects on the given keys
Filter array of objects on value or index
Implement browser history
Array with event listeners
Implement getElementByClassName() function
Implement getByClassNameHierarchy() function
Find element with the given color property
Localstorage with expiry
Machine coding practice
Practice playground
Multi-Stepper component in React
Switch-Case component in React
usePrevious() hook in React
Design Pattern
Singleton
Observer
Circuit Breaker
Proxy
Builder
Prototype
Iterator
Resource / Object pool
Chain of responsibility - 🆕
Visitor - 🆕
Command - 🆕
Composite - 🆕
Mediator - 🆕
Memento - 🆕
State - 🆕
Stratergy - 🆕
Template method - 🆕
Adapter - 🆕
Bridge - 🆕
Decorator - 🆕
Flyweight - 🆕
Facade - 🆕
Factory - 🆕
Rendering Pattern
Container/presentational pattern in React
Higher-order component pattern in React
Provider data passing pattern in React
Incremental static re-rendering vs Server-side generated
Client-side rendering vs Server-side rendering
Selective vs Progressive Hydration
Compound pattern in React
Optimization Techniques
Load script efficiently with async and defer
Tress shaking
Code splitting
Reactivity in JavaScript frameworks
Pagination - Offset vs. Cursor-Based
Adaptive loading
List virtualization
Core web vitals
Static import
Dynamic import
Optimizing loading sequence
Import on Visibility
Import on Interaction
Preload and Prefetch
Third party libraries optimization
Compression for better performance
Effecient loading of media
Periodically synchronize data in the background
Web fundamentals
How a webpage is rendered in the browser
Testing startergies
Different ways to host a frontend application
REST API vs SOAP API - 🆕
gRPC v/s GraphQL - 🆕
What is WebRTC - 🆕
Progressive Web App - 🆕
Understanding CDN - 🆕
Different way for real-time data exchange - 🆕
Understanding and optimizing privacy - 🆕
Web caching for unreliable networks - 🆕
Network reliability - 🆕
Different frontend architectures
Multi-page application vs Single-page application
Test automation
Error handling
Web security
Cross-site scripting (XSS)
Cross-site forgery (CSRF)
XML Enternal Entity (XEE)
Authenticaion and its best practices
Authorization and its best practices
Denial of Service (DDOS)
CORS attack
Cross frame scripting
Keeping web safe and secure
CSP directives and its secure implementation
Prototype pollution attacks
Server-side request forgery
Session management and its best practices - 🆕
Code Injection
State Management
Cookies, Session, Local storage, Indexdb
Microstate management with Zustand
Data Normalization
React-Query caching the data
Flux architecture and its alternatives - 🆕
MobX - 🆕
Redux - 🆕
Styling
Style guide
Different ways to style a react component
Desing system
Understanding and optimizing internationalization
Understanding and optimizing accessibility
Code management
Monorepo vs Polyrepo
PR template
Code review stratergies
Branch Management
Interview Guide
What is system design?
What to expect in Frontend Interview?
RADIO stratergy for system design
How to ace the interviews
Cheat Sheet
React Hooks 🆕
usePrevious() hook
useIdle() hook
useAsync() hook
useDebounce() hook
useThrottle() hook
useResponsive() hook
useWhyDidYouUpdate() hook
useOnScreen() hook
useScript() hook
useOnClickOutside() hook
useHasFocus() hook
useToggle() hook
useCopy() hook
useLockedBody() hook in React
Low-Level Design / Machine coding
Tic tac toe game with bot
Implement Feature Flag component in React
Multi-Stepper component in React
Switch-Case component in React
Implement Infinite Scroll in React
Two-step login form in React
Editable todo-list in React
Search with pagination in Reactjs
Responsive slideshow in Reactjs
Create responsive slideshow gallery in Reactjs
Create a lightbox (modal-image-gallery) in Reactjs
Functional modal component in Reactjs
Detect overlapping circles in React
Animate elements in a sequence
Preview zoomed image on Hover
Search with Autocomplete - React
Image auto carousel in React
Search with autosuggestion in VanillaJs
Pagination component in React
Typing effect component in react
Scroll indicator in React
Toggle switch in React
Accordion in React
Capture product visible on viewport when user stops scrolling
Create website walkthrough assistant in JavaScript
Number increment counter in React
Highlight text on selection in React 🆕
Batch api calls in sequence in React 🆕
Time in human readable format in React 🆕
Image comparison slider in React - 🆕
Frontend System Design Questions
Sample- Design a video streaming app like youtube
Design a trello / kanban board
Design a video streaming app like youtube, netflix, prime
Design an food order app like Swiggy, Ubereats
Design collaborative text editor
Design an form enricher, shortner sdk
Design news feeds of Facebook, Twitter, Linkedin
Design a configurable frontend application with different login types
Designing the frontend of the group or suite of apps
Designing the frontend of Pinterest or Google Photos
Design the frontend of the instagram
Design the frontend of the E-commerce APP
Design an online javascript coding platform
Design a messaging application like Slack
Design a hotel, housing booking service like airbnb
Design an meeting booking app like Calendly and Topmate.io
Design a music streaming webapp like spotify, gaana.com
Design a video conferencing app like Google meet, Zoom - 🆕
Design linkedin / peerlist (A professional network to showcase skills)
Design a todo list
Desing a role-based application (Privelages, restriction)
Design a feature-based application (A/B testing) feature flag
Design an analytics SDK (Collect user and website data)
Design a routing logic with two paths for every step
Design a pictonary game for remote team to collaborate
Design a news website
Design an no code form builder like Google forms
Design slido
Desing a offer validation service (Current offer is valid till X date)
Design an appointment, dining, movie booking app
Design a condition oversability application which works with rule When X, If meets codition Y, Do this action
Design an event listing web app
Design an memebership web app
Design an lucid admin dashboard
Design a google drive / dropbox
Design Q and A web app
Design a poll widget
Design a chat widget
Design an email client
Design an training website, where move to the next step when the previous step is done and require X percentage to pass
Design an online text and video testomonial collector (SDK that can be injected)
Design high frequency trading platform like Stock exchange
Quick Revision
5 hooks to improve performance in React App
“Speed by a thousand cuts” - Different loading strategies to optimize the website speed
Understanding closure in JavaScript
Understanding powerful Array.reduce() method
Function & this in JavaScript
Functions with default parameters in javascript
What are Pure and Impure functions in JavaScript
Javascript SET datastructure
Javascript MAP Datastructure
Javascript promise
A learners guide to JavaScript promises