JavaScript Coding Questions

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

• 3. implement Array.prototype.flat()JavaScriptmedium22010 accepted
• 4. implement basic throttle()JavaScriptLodashmedium15990 accepted
• 16. create an Event EmitterJavaScriptmedium9840 accepted
• 2. implement curry() with placeholder supportJavaScriptmedium8121 accepted
• 14. Implement a general memoization function - `memo()`JavaScriptmedium7550 accepted
• 32. implement `Promise.all()`JavaScriptmedium7389 accepted
• 176. undefined to nullJavaScriptmedium6390 accepted
• 23. create a sum()JavaScriptmedium5888 accepted
• 7. implement debounce() with leading & trailing optionJavaScriptLodashmedium5725 accepted
• 9. decode messageJavaScriptmedium5685 accepted
• 10. first bad versionJavaScriptAlgorithmmedium5535 accepted
• 5. implement throttle() with leading & trailing optionJavaScriptLodashmedium5476 accepted
• 58. get DOM tree heightJavaScriptAlgorithmDOMmedium5133 accepted
• 151. implement Array.prototype.map()JavaScriptmedium4948 accepted
• 29. implement async helper - `sequence()`JavaScriptmedium4007 accepted
• 33. implement `Promise.allSettled()`JavaScriptmedium3976 accepted
• 34. implement `Promise.any()`JavaScriptmedium3825 accepted
• 64. auto-retry Promise on rejectionJavaScriptmedium3605 accepted
• 113. Virtual DOM IJavaScriptAlgorithmDOMmedium3586 accepted
• 92. throttle PromisesJavaScriptmedium3503 accepted
• 161. toBe() or not.toBe()JavaScriptmedium3312 accepted
• 13. Implement a Queue by using StackJavaScriptAlgorithmmedium3111 accepted
• 104. Traverse DOM level by levelJavaScriptAlgorithmDOMmedium2896 accepted
• 57. create an ObservableJavaScriptmedium2857 accepted
• 68. get DOM tagsJavaScriptAlgorithmDOMmedium2832 accepted
• 146. implement Array.prototype.reduce()JavaScriptmedium2787 accepted
• 67. create your own PromiseJavaScriptmedium2610 accepted
• 30. implement async helper - `parallel()`JavaScriptmedium2592 accepted
• 20. Detect data type in JavaScriptJavaScriptmedium2507 accepted
• 26. implement Object.assign()JavaScriptmedium2487 accepted
• 12. implement Immutability helperJavaScriptmedium2466 accepted
• 168. move zerosJavaScriptAlgorithmmedium2466 accepted
• 110. serialize and deserialize binary treeJavaScriptAlgorithmmedium2344 accepted
• 46. implement `_.once()`JavaScriptLodashmedium2301 accepted
• 63. create `_.cloneDeep()`JavaScriptAlgorithmLodashmedium2255 accepted
• 56. call APIs with paginationJavaScriptmedium2047 accepted
• 85. implement `_.get()`JavaScriptLodashmedium1926 accepted
• 61. create your own `Function.prototype.call`JavaScriptmedium1902 accepted
• 103. implement Math.sqrt()JavaScriptAlgorithmmedium1879 accepted
• 125. implement classNames()JavaScriptmedium1866 accepted
• 123. implement Promise.prototype.finally()JavaScriptmedium1833 accepted
• 69. implement deep equal `_.isEqual()`JavaScriptLodashmedium1747 accepted
• 83. create an intervalJavaScriptmedium1619 accepted
• 173. uncompress stringJavaScriptstringalgorithmmedium1594 accepted
• 158. Previous Left SiblingJavaScriptDOMmedium1580 accepted
• 130. create LazyMan()JavaScriptmedium1559 accepted
• 53. write your own `extends` in es5JavaScriptmedium1491 accepted
• 131. implement _.chunk()JavaScriptLodashmedium1472 accepted
• 122. implement memoizeOne()JavaScriptmedium1456 accepted
• 86. Generate Fibonacci NumberJavaScriptAlgorithmmedium1399 accepted
• 66. remove duplicates from an arrayJavaScriptAlgorithmmedium1317 accepted
• 156. implement `_.set()`JavaScriptLodashmedium1264 accepted
• 36. create a fake timer(setTimeout)JavaScriptmedium1218 accepted
• 152. Find Top k ElementsJavaScriptAlgorithmmedium1202 accepted
• 135. localStorage with expirationJavaScriptmedium1193 accepted
• 65. add comma to numberJavaScriptmedium1187 accepted
• 24. create a Priority Queue in JavaScriptJavaScriptAlgorithmmedium1183 accepted
• 59. create a browser historyJavaScriptmedium1175 accepted
• 90. write your own `instanceof`JavaScriptmedium1156 accepted
• 55. highlight keywords in HTML stringJavaScriptAlgorithmmedium1117 accepted
• 22. implement JSON.parse()JavaScriptmedium1083 accepted
• 43. implement Quick SortJavaScriptAlgorithmmedium1058 accepted
• 27. implement completeAssign() JavaScriptmedium1049 accepted
• 101. merge identical API callsJavaScriptmedium1030 accepted
• 139. implement _.partial()JavaScriptLodashmedium1006 accepted
• 41. implement Merge SortJavaScriptAlgorithmmedium1002 accepted
• 52. create a middleware systemJavaScriptmedium976 accepted
• 95. implement String.prototype.trim()JavaScriptmedium926 accepted
• 82. find available meeting slotsJavaScriptAlgorithmmedium924 accepted
• 79. convert snake_case to camelCaseJavaScriptmedium919 accepted
• 170. Generate CSS Selector for target elementJavaScriptmedium910 accepted
• 88. support negative Array index in JavaScriptJavaScriptmedium833 accepted
• 166. validate number stringJavaScriptAlgorithmstringmedium833 accepted
• 45. find the K-th largest element in an unsorted arrayJavaScriptAlgorithmmedium801 accepted
• 117. event delegationJavaScriptmedium790 accepted
• 136. find median of two sorted arrayJavaScriptAlgorithmmedium783 accepted
• 149. interpolationJavaScriptmedium775 accepted
• 111. Count palindromic substringsJavaScriptAlgorithmstringmedium705 accepted
• 108. Implement a Stack by using QueueJavaScriptAlgorithmmedium679 accepted
• 132. the angle between hour hand and minute hand of a clockJavaScriptmedium677 accepted
• 119. create a tokenizerJavaScriptmedium634 accepted
• 112. remove duplicate characters in a stringJavaScriptAlgorithmstringmedium606 accepted
• 177. Implement Object.groupBy()JavaScriptmedium590 accepted
• 172. implement `Math.clz32()`JavaScriptmedium586 accepted
• 153. uglify CSS class namesJavaScriptmedium582 accepted
• 134. create your own CookieJavaScriptmedium577 accepted
• 70. implement Observable.from()JavaScriptmedium557 accepted
• 84. create a fake timer (setInterval)JavaScriptmedium514 accepted
• 71. implement Observable SubjectJavaScriptmedium492 accepted
• 99. extract all anchor element from HTML string JavaScriptmedium480 accepted
• 171. create callback on message channelJavaScriptmedium475 accepted
• 164. implement Immer produce()JavaScriptmedium456 accepted
• 75. implement BigInt subtractionJavaScriptAlgorithmmedium433 accepted
• 98. validate an IP addressJavaScriptmedium383 accepted
• 169. LRU - Chrome storage automatic evictionJavaScriptAlgorithmmedium360 accepted
• 78. convert HEX color to RGBAJavaScriptmedium319 accepted
• 143. Virtual DOM IV - JSX 1JavaScriptmedium302 accepted
• 124. calculate arithmetic expressionJavaScriptAlgorithmmedium237 accepted
• 76. implement BigInt addition with signJavaScriptmedium199 accepted
• 160. implement atob()JavaScriptmedium192 accepted
• 144. serialize and deserialize data types not supported in JSONJavaScriptmedium163 accepted
• 114. implement BigInt multiplicationJavaScriptmedium154 accepted
• 150. Virtual DOM V - JSX 2JavaScriptmedium150 accepted
• 77. implement BigInt subtraction with signJavaScriptmedium118 accepted
• 115. implement BigInt divisionJavaScriptmedium77 accepted
• 126. BigDecimal additionJavaScriptAlgorithmmedium76 accepted
• 128. BigDecimal multiplicationJavaScriptAlgorithmmedium40 accepted
• 129. BigDecimal DivisionJavaScriptAlgorithmmedium40 accepted
• 127. BigDecimal subtractionJavaScriptAlgorithmmedium35 accepted
• 175. CSS Grid Layout auto-placement algorithm - denseJavaScriptCSSmedium17 accepted