JavaScript Coding Questions

As a Front-End developer, JavaScript is the core skill of everything

• 3. implement Array.prototype.flat()JavaScriptmedium24135 accepted
• 4. implement basic throttle()JavaScriptLodashmedium17720 accepted
• 16. create an Event EmitterJavaScriptmedium10619 accepted
• 2. implement curry() with placeholder supportJavaScriptmedium9186 accepted
• 32. implement `Promise.all()`JavaScriptmedium8300 accepted
• 14. Implement a general memoization function - `memo()`JavaScriptmedium8280 accepted
• 8. can you shuffle() an array?JavaScriptmedium7365 accepted
• 23. create a sum()JavaScriptmedium6513 accepted
• 7. implement debounce() with leading & trailing optionJavaScriptLodashmedium6371 accepted
• 9. decode messageJavaScriptmedium6250 accepted
• 5. implement throttle() with leading & trailing optionJavaScriptLodashmedium6117 accepted
• 10. first bad versionJavaScriptAlgorithmmedium6064 accepted
• 58. get DOM tree heightJavaScriptAlgorithmDOMmedium5417 accepted
• 151. implement Array.prototype.map()JavaScriptmedium5314 accepted
• 33. implement `Promise.allSettled()`JavaScriptmedium4527 accepted
• 29. implement async helper - `sequence()`JavaScriptmedium4519 accepted
• 165. remove charactersAlgorithmmedium4372 accepted
• 34. implement `Promise.any()`JavaScriptmedium4350 accepted
• 64. auto-retry Promise on rejectionJavaScriptmedium4257 accepted
• 92. throttle PromisesJavaScriptmedium3968 accepted
• 113. Virtual DOM IJavaScriptAlgorithmDOMmedium3798 accepted
• 161. toBe() or not.toBe()JavaScriptmedium3497 accepted
• 13. Implement a Queue by using StackJavaScriptAlgorithmmedium3491 accepted
• 57. create an ObservableJavaScriptmedium3070 accepted
• 146. implement Array.prototype.reduce()JavaScriptmedium3068 accepted
• 104. Traverse DOM level by levelJavaScriptAlgorithmDOMmedium3020 accepted
• 68. get DOM tagsJavaScriptAlgorithmDOMmedium2962 accepted
• 30. implement async helper - `parallel()`JavaScriptmedium2905 accepted
• 20. Detect data type in JavaScriptJavaScriptmedium2883 accepted
• 67. create your own PromiseJavaScriptmedium2839 accepted
• 26. implement Object.assign()JavaScriptmedium2820 accepted
• 12. implement Immutability helperJavaScriptmedium2768 accepted
• 46. implement `_.once()`JavaScriptLodashmedium2582 accepted
• 168. move zerosJavaScriptAlgorithmmedium2562 accepted
• 63. create `_.cloneDeep()`JavaScriptAlgorithmLodashmedium2549 accepted
• 110. serialize and deserialize binary treeJavaScriptAlgorithmmedium2447 accepted
• 56. call APIs with paginationJavaScriptmedium2233 accepted
• 85. implement `_.get()`JavaScriptLodashmedium2161 accepted
• 61. create your own `Function.prototype.call`JavaScriptmedium2130 accepted
• 125. implement classNames()JavaScriptmedium2052 accepted
• 69. implement deep equal `_.isEqual()`JavaScriptLodashmedium2047 accepted
• 123. implement Promise.prototype.finally()JavaScriptmedium2022 accepted
• 103. implement Math.sqrt()JavaScriptAlgorithmmedium1991 accepted
• 83. create an intervalJavaScriptmedium1829 accepted
• 130. create LazyMan()JavaScriptmedium1723 accepted
• 173. uncompress stringJavaScriptstringalgorithmmedium1681 accepted
• 53. write your own `extends` in es5JavaScriptmedium1661 accepted
• 158. Previous Left SiblingJavaScriptDOMmedium1631 accepted
• 122. implement memoizeOne()JavaScriptmedium1568 accepted
• 131. implement _.chunk()JavaScriptLodashmedium1566 accepted
• 86. Generate Fibonacci NumberJavaScriptAlgorithmmedium1550 accepted
• 66. remove duplicates from an arrayJavaScriptAlgorithmmedium1451 accepted
• 36. create a fake timer(setTimeout)JavaScriptmedium1356 accepted
• 24. create a Priority Queue in JavaScriptJavaScriptAlgorithmmedium1336 accepted
• 65. add comma to numberJavaScriptmedium1326 accepted
• 156. implement `_.set()`JavaScriptLodashmedium1318 accepted
• 135. localStorage with expirationJavaScriptmedium1317 accepted
• 59. create a browser historyJavaScriptmedium1302 accepted
• 90. write your own `instanceof`JavaScriptmedium1253 accepted
• 152. Find Top k ElementsJavaScriptAlgorithmmedium1237 accepted
• 55. highlight keywords in HTML stringJavaScriptAlgorithmmedium1213 accepted
• 43. implement Quick SortJavaScriptAlgorithmmedium1207 accepted
• 22. implement JSON.parse()JavaScriptmedium1198 accepted
• 27. implement completeAssign() JavaScriptmedium1171 accepted
• 41. implement Merge SortJavaScriptAlgorithmmedium1160 accepted
• 101. merge identical API callsJavaScriptmedium1133 accepted
• 52. create a middleware systemJavaScriptmedium1096 accepted
• 139. implement _.partial()JavaScriptLodashmedium1085 accepted
• 95. implement String.prototype.trim()JavaScriptmedium1018 accepted
• 82. find available meeting slotsJavaScriptAlgorithmmedium1012 accepted
• 79. convert snake_case to camelCaseJavaScriptmedium1006 accepted
• 170. Generate CSS Selector for target elementJavaScriptmedium956 accepted
• 88. support negative Array index in JavaScriptJavaScriptmedium899 accepted
• 45. find the K-th largest element in an unsorted arrayJavaScriptAlgorithmmedium896 accepted
• 166. validate number stringJavaScriptAlgorithmstringmedium861 accepted
• 117. event delegationJavaScriptmedium839 accepted
• 136. find median of two sorted arrayJavaScriptAlgorithmmedium822 accepted
• 149. interpolationJavaScriptmedium805 accepted
• 111. Count palindromic substringsJavaScriptAlgorithmstringmedium743 accepted
• 108. Implement a Stack by using QueueJavaScriptAlgorithmmedium732 accepted
• 177. Implement Object.groupBy()JavaScriptmedium726 accepted
• 132. the angle between hour hand and minute hand of a clockJavaScriptmedium707 accepted
• 119. create a tokenizerJavaScriptmedium677 accepted
• 112. remove duplicate characters in a stringJavaScriptAlgorithmstringmedium634 accepted
• 134. create your own CookieJavaScriptmedium630 accepted
• 153. uglify CSS class namesJavaScriptmedium609 accepted
• 70. implement Observable.from()JavaScriptmedium596 accepted
• 172. implement `Math.clz32()`JavaScriptmedium595 accepted
• 84. create a fake timer (setInterval)JavaScriptmedium563 accepted
• 71. implement Observable SubjectJavaScriptmedium539 accepted
• 99. extract all anchor element from HTML string JavaScriptmedium501 accepted
• 171. create callback on message channelJavaScriptmedium495 accepted
• 75. implement BigInt subtractionJavaScriptAlgorithmmedium488 accepted
• 164. implement Immer produce()JavaScriptmedium483 accepted
• 98. validate an IP addressJavaScriptmedium411 accepted
• 169. LRU - Chrome storage automatic evictionJavaScriptAlgorithmmedium387 accepted
• 78. convert HEX color to RGBAJavaScriptmedium346 accepted
• 143. Virtual DOM IV - JSX 1JavaScriptmedium313 accepted
• 124. calculate arithmetic expressionJavaScriptAlgorithmmedium255 accepted
• 76. implement BigInt addition with signJavaScriptmedium229 accepted
• 160. implement atob()JavaScriptmedium200 accepted
• 114. implement BigInt multiplicationJavaScriptmedium179 accepted
• 144. serialize and deserialize data types not supported in JSONJavaScriptmedium174 accepted
• 150. Virtual DOM V - JSX 2JavaScriptmedium167 accepted
• 77. implement BigInt subtraction with signJavaScriptmedium138 accepted
• 115. implement BigInt divisionJavaScriptmedium86 accepted
• 126. BigDecimal additionJavaScriptAlgorithmmedium82 accepted
• 128. BigDecimal multiplicationJavaScriptAlgorithmmedium46 accepted
• 129. BigDecimal DivisionJavaScriptAlgorithmmedium44 accepted
• 127. BigDecimal subtractionJavaScriptAlgorithmmedium39 accepted
• 175. CSS Grid Layout auto-placement algorithm - denseJavaScriptCSSmedium21 accepted