BFE
.dev
buy us
a coffee
EN
Practice
Explore
EN
JavaScript Coding Questions
As a Front-End developer, JavaScript is the core skill of everything
Sort
Difficulty
Solved status
Company
Sort: most liked
Difficulty: easy
1. implement curry()
JavaScript
easy
161 likes
3. implement Array.prototype.flat()
JavaScript
easy
80 likes
23. create a sum()
JavaScript
easy
67 likes
19. find corresponding node in two identical DOM tree
JavaScript
easy
54 likes
176. undefined to null
JavaScript
easy
50 likes
11. what is Composition? create a pipe()
JavaScript
easy
41 likes
6. implement basic debounce()
JavaScript
Lodash
easy
35 likes
28. implement clearAllTimeout()
JavaScript
easy
34 likes
18. Improve a function
JavaScript
easy
32 likes
148. create a counter object
JavaScript
easy
31 likes
159. implement promisify()
JavaScript
easy
27 likes
17. Create a simple store for DOM element
JavaScript
easy
27 likes
167. Intersection of unsorted arrays
JavaScript
Algorithm
easy
25 likes
60. create your own `new` operator
JavaScript
easy
24 likes
89. Next Right Sibling
JavaScript
DOM
easy
21 likes
35. implement `Promise.race()`
JavaScript
easy
21 likes
25. Reorder array with new indexes
JavaScript
Algorithm
easy
21 likes
15. implement a simple DOM wrapper to support method chaining like jQuery
JavaScript
easy
21 likes
162. find the single integer
JavaScript
Algorithm
easy
19 likes
154. Two-way binding
JavaScript
DOM
easy
18 likes
155. create a count function
JavaScript
easy
16 likes
118. Virtual DOM II - createElement
JavaScript
easy
16 likes
157. semver compare
JavaScript
easy
15 likes
54. flatten Thunk
JavaScript
easy
15 likes
46. implement `_.once()`
JavaScript
Lodash
easy
15 likes
39. implement range()
JavaScript
easy
15 likes
145. most frequently occurring character
JavaScript
easy
14 likes
121. A number sequence
JavaScript
easy
13 likes
97. compress a string
JavaScript
string
easy
13 likes
47. reverse a linked list
JavaScript
Algorithm
easy
13 likes
38. implement `jest.spyOn()`
JavaScript
easy
13 likes
31. implement async helper - `race()`
JavaScript
easy
12 likes
147. Pick up stones
JavaScript
easy
11 likes
81. merge sorted arrays
JavaScript
Algorithm
easy
11 likes
138. Intersection of two sorted arrays
JavaScript
Algorithm
easy
10 likes
116. implement Object.is()
JavaScript
easy
10 likes
91. invert a binary tree
JavaScript
Algorithm
easy
10 likes
40. implement Bubble Sort
JavaScript
Algorithm
easy
10 likes
163. integer to roman numerals
JavaScript
Algorithm
easy
9 likes
107. Find the largest difference
JavaScript
Algorithm
easy
9 likes
106. Find two numbers that sum up to 0
JavaScript
Algorithm
easy
9 likes
94. implement your own `Object.create`
JavaScript
easy
9 likes
93. Generate Fibonacci Number with recursion
JavaScript
easy
9 likes
87. longest substring with unique characters
JavaScript
Algorithm
easy
9 likes
133. roman numerals to integer
JavaScript
easy
8 likes
109. implement `Math.pow()`
JavaScript
Algorithm
easy
8 likes
105. find the first duplicate character in a string
JavaScript
string
easy
8 likes
100. detect circle in linked list
JavaScript
Algorithm
easy
8 likes
142. lit-html 1 - tagged templates
JavaScript
lit-html
easy
7 likes
140. Virtual DOM III - Functional Component
JavaScript
easy
7 likes
37. implement Binary Search (unique)
JavaScript
easy
7 likes
120. create `isPrime()`
JavaScript
Algorithm
easy
6 likes
102. validate string of parentheses
JavaScript
Algorithm
string
easy
6 likes
74. implement Observable Transformation Operators
JavaScript
easy
6 likes
72. implement Observable interval()
JavaScript
easy
6 likes
50. search element right before target with Binary Search(possible duplicate array)
JavaScript
Algorithm
easy
6 likes
96. count "1" in binary form
JavaScript
easy
5 likes
62. implement BigInt addition
JavaScript
Algorithm
easy
5 likes
51. search element right after target with Binary Search(possible duplicate array)
JavaScript
Algorithm
easy
5 likes
49. search last index with Binary Search(possible duplicate array)
JavaScript
Algorithm
easy
5 likes
48. search first index with Binary Search(possible duplicate array)
JavaScript
Algorithm
easy
5 likes
42. implement Insertion Sort
JavaScript
Algorithm
easy
5 likes
141. implement btoa()
JavaScript
easy
4 likes
73. implement Observable fromEvent()
JavaScript
easy
4 likes
44. implement Selection Sort
JavaScript
Algorithm
easy
4 likes