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TypeScript Interview Questions

380+ most important TypeScript interview questions on library APIs, utility types, algorithms, and building strong, typed components.

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Make CounterImplement a function that accepts an integer value and returns a function that can be repeatedly called to return increasing values
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MeanImplement a function that finds the mean of the values inside an array
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Function.prototype.callImplement the Function.prototype.call() function that calls the function with a given `this` value and provided arguments
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Min ByImplement a function that finds the minimum element based on the specified criteria
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Selection SortImplement a function that performs a selection sort
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StackImplement a stack data structure containing the common stack methods
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Type UtilitiesImplement utilities to determine primitive variable types in JavaScript
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Array.prototype.reduceImplement the Array.prototype.reduce() method
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Count Set Bits in a Binary NumberImplement a function to find set bits in binary representation of a given integer
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CycleImplement a function that takes one or more values and returns a function that cycles through those values each time it is called
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Find Duplicates in ArrayImplement a function to check if there are any duplicate numbers in the array
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Find Missing Number in SequenceImplement a function to find the missing element in a sorted array
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Insertion SortImplement a function that performs an insertion sort
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Optimal Stock TradingImplement a function to find the maximum profit achievable by buying and selling a stock once
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Pair sumImplement a function to find two numbers within an array of integers that add up to a target integer
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String AnagramImplement a function to determine if two strings are anagram of each other
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Type Utilities IIImplement utilities to determine non-primitive variable types in JavaScript
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Binary Tree Maximum DepthImplement a function to find the maximum depth of a binary tree
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Flip Binary TreeImplement a function to flip the nodes in a binary tree
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Staircase Climbing CombinationsImplement a function to find the number of ways to reach at the top of staircase
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Balanced BracketsImplement a function to determine if a string contains balanced brackets
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Binary Tree EqualImplement a function to determine whether two binary trees are equal
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Bit CountingImplement a function to find number of set bits from 0 to n
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Bit ReversalImplement a function to flip the order of the bits in a given number
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Linked List ReversalImplement a function to reverse a linked list
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String PalindromeImplement a function to determine if a string is a palindrome
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Linked List Detect CycleImplement a function to detect if there are cycles in a linked list
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Binary Tree SubtreeImplement a function to check if a binary tree is a subtree of another binary tree
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Linked Lists Combine Two SortedImplement a function to combine two sorted linked list
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Meeting CalendarImplement a function to check if all meetings can be attended
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Array Product Excluding CurrentImplement a function to find the product of elements in an array excluding the current element
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Binary SearchImplement a function that performs binary search on an array of numbers
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Breadth-first SearchImplement a breadth-first search algorithm that traverses a directed graph in a breadth-first manner
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Count ByImplement a function that counts the number of times a value appears in an array based on a function or property name
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CurryImplement a function that transforms a function that takes multiple arguments into a function that can be repeatedly called with only one argument at a time
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DebounceImplement a function to limit how many times a function can be executed by delaying the execution of the function until after a specified time after its last execution attempt
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Depth-first SearchImplement a depth-first search algorithm that traverses a directed graph in a depth-first manner
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Heap SortImplement a function that performs a heap sort
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Is the Graph a TreeImplement a function to determine if a graph is a valid tree
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Maximum Water Trapped Between WallsImplement a function to find the maximum water volume between two walls in an array of walls
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PromisifyImplement a function that takes a function following the common error-first callback style and returns a version that returns promises
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QueueImplement a queue data structure containing the common queue methods
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ThrottleImplement a function to control the execution of a function by limiting how many times it can execute over time
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ClassnamesImplement a function that conditionally joins CSS class names together
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Data MergingImplement a function to merge rows of data from the same user
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Event EmitterImplement a class that can subscribe to and emit events that trigger attached callback functions
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FlattenImplement a function that recursively flattens an array into a single level deep
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getElementsByStyleImplement a function to get all DOM elements that are rendered using the specified style
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HTML SerializerImplement a function to serialize an object into an HTML string with indentation
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JSON.stringifyImplement a function that converts a JavaScript value into a JSON string
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List FormatImplement a function that formats a list of items into a single readable string
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MemoizeImplement a function that returns a memoized version of a function which accepts a single argument
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Merge SortImplement a function that performs a recursive merge sort
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Promise.allImplement the Promise.all() function that resolves to an array of results if all the input elements are resolved or rejects otherwise
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Promise.anyImplement the Promise.any() function that resolves when any of the input elements are resolved
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Quick SortImplement a function that performs a recursive quick sort
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Squash ObjectImplement a function that returns a new object after squashing the input object into a single level of depth
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Topological SortImplement a function that performs a topological sort
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Binary Tree Level Order TraversalImplement a function to find the level order traversal of a binary tree
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Deep CloneImplement a function that performs a deep copy of a value
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Deep EqualImplement a function that determines if two values are equal
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getElementsByClassNameImplement a function to get all DOM elements that contain the specified classes
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Map Async LimitImplement a function that maps an array of items with an asynchronous mapping function while not exceeding the concurrency limit
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Maximum Sum in Contiguous ArrayImplement a function to find the subarray with the maximum sum
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Smallest element in rotated sorted arrayImplement a function to find the smallest element in rotated sorted array
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Deep OmitImplement a function that removes specified keys and their corresponding values from an object, including nested objects or arrays
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Find Element in Rotated ArrayImplement a function to find an integer in a rotated sorted array
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Maximum Product in Contiguous ArrayImplement a function to find the subarray which has the largest product
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Binary Search Tree Kth Smallest ElementImplement a function to find the kth smallest node in a BST
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Binary Search Tree Lowest Common AncestorImplement a function to find the LCA in a binary search tree
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Count Islands in a GridImplement a function to count distinct islands in a 2D binary grid
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Delete Nth Node from End of Linked ListImplement a function to delete the nth node from the end of a linked list
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Distinct Paths in GridImplement a function to calculate distinct paths for a robot moving on an m x n grid
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Matrix ZeroingImplement a function to set matrix rows and columns to zero
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Merge Overlapping IntervalsImplement a function to merge overlapping intervals
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Most Common ElementsImplement a function to determine the most common elements in an integer array
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Neighborhood TheftImplement a function to find maximum money to rob without alerting police
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Rearrange Linked ListImplement a function to rearrange the nodes in a linked list
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Sum Without AdditionImplement a function to find the sum of two integers without using + and - operator
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Triplet SumImplement a function to find all unique triplets with distinct indices that sum to 0
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Validate Binary Search TreeImplement a function to validate whether a binary tree is a valid binary search tree
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Combinations for Target SumImplement a function to count combinations that sum to the target
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Course DependencyImplement a function to check if all courses can be completed given prerequisites
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Decode MessageImplement a function to count ways to decode a numeric string
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Longest Consecutive Number SequenceImplement a function to find the length of the longest consecutive number sequence
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Longest Increasing SubsequenceImplement a function to find the length of the longest increasing subsequence
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Minimum Coins for ChangeImplement a function to return minimum coins needed to make the given amount
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Palindromic SubstringsImplement a function to count all palindromic substrings in a string
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Segment WordsImplement a function to check whether a string be formed from dictionary words
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String Anagram GroupsImplement a function to group an array of strings into anagrams
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Task CoordinationImplement a function to find minimum intervals for tasks with cooldown
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Trie (Prefix Tree)Implement a trie-prefix-tree with insert, search, and starts with functionality
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Binary Tree Rebuilding from Preorder and Inorder TraversalsImplement a function to construct a binary tree from preorder and inorder traversals
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Disjoint IntervalsImplement a function to determine the minimum amount of removals to get non-overlapping intervals
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End of Array ReachableImplement a function to determine if the end of the array is reachable
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Find the Longest Palindromic SubstringImplement a function to find the longest palindromic substring
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Find Word in GridImplement a function to check the existence of a word in a grid
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Graph Count Connected ComponentsImplement a function to count connected components in a graph
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Longest Common SubsequenceImplement a function to find the longest common subsequence in two strings
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TypeScript Interview Questions

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