JavaScript fundamental - Exercises, Practice, Solution
This resource offers a total of 600 JavaScript fundamental problems for practice. It includes 150 main exercises, each accompanied by solutions, detailed explanations, and three related problems.
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1. Compare Objects for Equivalent Properties
Write a JavaScript program to compare two objects to determine if the first contains equivalent property values to the second one.
2. Copy String to Clipboard
Write a JavaScript program to copy a string to the clipboard.
3. CSV String to 2D Array
Write a JavaScript program to convert a comma-separated value (CSV) string to a 2D array.
4. CSV to 2D Array of Objects
Write a JavaScript program to convert a comma-separated value (CSV) string to a 2D array of objects. The first row of the string is used as the title row.
5. Array of Objects to CSV String
Write a JavaScript program to convert an array of objects to a comma-separated value (CSV) string that contains only the columns specified.
6. Target Value in Nested JSON
Write a JavaScript program to target a given value in a nested JSON object based on the given key.
7. Number to Array of Digits
Write a JavaScript program to convert a specified number into an array of digits.
8. Filter Specified Values from Array
Write a JavaScript program to filter out the specified values from a specified array. Return the original array without filtered values.
9. All Combinations from Array of Numbers
Write a JavaScript program to combine the numbers of a given array into an array containing all combinations.
10. Extract Values by Indexes from Array
Write a JavaScript program to extract values at specified indexes from a specified array.
11. Generate Random Hexadecimal Color Code
Write a JavaScript program to generate a random hexadecimal color code.
12. Remove Non-Printable ASCII from String
Write a JavaScript program to remove non-printable ASCII characters from a given string.
13. String Length in Bytes
Write a JavaScript program to convert a given string's length to bytes.
14. Replace Multiple Object Keys
Write a JavaScript program to replace multiple object keys' names with the values provided.
15. Min-Max Value of Array with Function
Write a JavaScript program to return the minimum-maximum value of an array, after applying the provided function to set a comparing rule.
16. Predicate Function Check for All Elements
Write a JavaScript function that returns true if the provided predicate function returns true for all elements in a collection, false otherwise.
17. Split Array into Two Groups
Write a JavaScript program to split the values of two given arrays into two groups. If an element in the filter is true, the corresponding element in the collection belongs to the first group; otherwise, it belongs to the second group.
18. Remove Left Elements from Array
Write a JavaScript program to remove specified elements from the left of a given array of elements.
19. Remove Right Elements from Array
Write a JavaScript program to remove specified elements from the right of a given array of elements.
20. Expand 3-Digit to 6-Digit Color Code
Write a JavaScript program to extend a 3-digit color code to a 6-digit color code.
21. Every nth Element in Array
Write a JavaScript program to get every nth element in a given array.
22. Filter Non-Unique Values in Array
Write a JavaScript program to filter out non-unique values in an array.
23. Filter Non-Unique with Comparator
Write a JavaScript program to filter out non-unique values in an array, based on a provided comparator function.
24. Decapitalize First Letter of String
Write a JavaScript program to dcapitalize the first letter of a string.
25. Create All Pairs from Arrays
Write a JavaScript program to create an array out of the arrays by creating each possible pair from the arrays.
26. Check y/yes or n/no in String
Write a JavaScript program that returns true if the string is y/yes or false if the string is n/no.
27. Find Common Elements with Comparator
Write a JavaScript program to find every element in any of the two given arrays at once, using the provided comparator function.
28. Measure Function Execution Time
Write a JavaScript program to measure the time a function to execute.
29. Convert Value to Safe Integer
Write a JavaScript program to convert a value to a safe integer.
30. Filter Elements Matching Values
Write a JavaScript program to filter out the element(s) of a given array that have one of the specified values.
31. All Elements Except First in Array
Write a JavaScript program to find all elements in a given array except the first one. Return the whole array if its length is 1.
32. Sum Array After Mapping Function
Write a JavaScript program to get the sum of a given array, after mapping each element to a value using the provided function.
33. Random Number in Range
Write a JavaScript program to generate a random number in the specified range.
34. Random Integer in Range
Write a JavaScript program to generate a random integer in the specified range.
35. Array of n Random Integers in Range
Write a JavaScript program to get an array of given n random integers in the specified range.
36. Invoke Functions with Arguments
Write a JavaScript program to create a function that invokes each provided function with the arguments it receives and returns the results.
37. Sort Array of Objects by Properties
Write a JavaScript program to get a sorted array of objects ordered by properties and orders.
38. Pad String on Both Sides
Write a JavaScript program to pad a string on both sides with the specified character, if it's shorter than the specified length.
39. Remove Keys from Object
Write a JavaScript program to remove the key-value pairs corresponding to the given keys from an object.
40. Create Key-Value Pair Array from Object
Write a JavaScript program to create an array of key-value pair arrays from a given object.
41. Object from Key-Value Pairs
Write a JavaScript program to create an object from the given key-value pairs.
42. Custom Coalesce Function
Write a JavaScript program to get a customized coalesce function that returns the first argument that returns true from the provided argument validation function.
43. Change Function to Variadic
Write a JavaScript program to change a function that accepts an array into a variadic function.
44. Remove Falsey Values from Array
Write a JavaScript program to remove false values from a given array.
45. Split Values into Two Groups by Filter
Write a JavaScript program to split values into two groups. If an element in the filter is true, the corresponding element in the collection belongs to the first group; otherwise, it belongs to the second group.
46. Curry a Function
Write a JavaScript program to curry (curries) a function.
47. Deep Comparison for Equivalence
Write a JavaScript program to perform a deep comparison between two values to determine if they are equivalent.
48. Array of Function Property Names
Write a JavaScript program to get an array of function property names from the own (and optionally inherited) enumerable properties of an object.
49. Retrieve Selected Properties from Object
Write a JavaScript program to retrieve a set of properties indicated by the given selectors from an object.
50. Integer to Suffix String with am/pm
Write a JavaScript program to convert an integer to a suffixed string, adding am or pm based on its value.
51. Get Current URL Parameters as Object
Write a JavaScript program to get an object containing the current URL parameters.
52. Group Array Elements by Function
Write a JavaScript program to group the elements of a given array based on the given function.
53. Initialize 2D Array with Size and Value
Write a JavaScript program to initialize a two-dimensional array of given size and value.
54. Array of Numbers in Specified Range
Write a JavaScript program to initialize an array containing numbers in the specified range. Start and end are inclusive of their common point of difference.
55. Join and Normalize URL Segments
Write a JavaScript program to join all given URL segments together, then normalize the resulting URL.
56. Check All Elements Equal in Array
Write a JavaScript program to check whether all elements in a given array are equal or not.
57. Average of Array with Mapping Function
Write a JavaScript program to compute the average of an array, after mapping each element to a value using the provided function.
58. Split Values into Groups by Predicate
Write a JavaScript program to split values into two groups according to a predicate function. This specifies which group an element in the input collection belongs to.
59. Invoke Function in Given Context
Write a JavaScript program to create a function that invokes fn in a given context. Optionally add any additional variables to the arguments beginning.
60. Invoke Object Method by Key
Write a JavaScript program to create a function that invokes the method at a given key of an object. Optionally, add any parameters that are supplied to the beginning of the arguments.
61. Cast Value to Array
Write a JavaScript program to cast the provided value as an array if it's not one.
62. Chain Asynchronous Functions
Write a JavaScript program to chain asynchronous functions.
63. Clone Regular Expression
Write a JavaScript program to clone a given regular expression.
64. Get First Non-Null/Undefined Argument
Write a JavaScript program to get the first non-null / undefined argument.
65. Add Console Log Colors
Write a JavaScript program to add special characters to text to print in color on the console (combined with console.log()).
66. Right-to-Left Function Composition
Write a JavaScript program to perform right-to-left function composition.
67. Left-to-Right Function Composition
Write a JavaScript program to perform left-to-right function composition.
68. Converge Function with Branching Functions
Write a JavaScript program that accepts a converging function and a list of branching functions. It returns a function that applies each branching function to the arguments. The results of the branching functions are passed as arguments to the converging function.
69. Group Array and Count Elements
Write a JavaScript program to group array elements based on the given function. It return the count of elements in each group.
70. Count Value in Array
Write a JavaScript program to count a value in an array.
71. Deep Clone Object
Write a JavaScript program to create a deep clone of an object.
72. Detect Mobile or Desktop
Write a JavaScript program to detect whether the website is opened on a mobile device or a desktop/laptop.
73. Difference Between Two Arrays with Mapping
Write a JavaScript program to return the difference between two arrays, after applying the provided function to each array element of both.
74. Filter Array by Comparator
Write a JavaScript program to filter out all values from an array for which the comparator function does not return true.
75. Elo Rating System Computation
Write a JavaScript program to compute the updated ratings between two or more opponents using the Elo rating system. It takes an array of pre-ratings and returns an array containing post-ratings. The array should be ordered from top to bottom (winner -> loser).
76. Execute Function for Array in Reverse Order
Write a JavaScript program to execute a provided function once for each array element, starting with the array's last element.
77. Iterate Over Object Properties
Write a JavaScript program to iterate over all the properties of an object, running a callback for each one.
78. Invert Key-Value Pairs in Object
Write a JavaScript program to invert the key-value pairs of an object, without mutating it. The corresponding inverted value of each inverted key is an array of keys responsible for generating the inverted value. If a function is supplied, it is applied to each inverted key.
79. Find Longest Iterable Object
Write a JavaScript program to take any number of iterable objects or objects with a length property and return the longest one.
80. Validate with Luhn Algorithm
Write a JavaScript program to implement the Luhn Algorithm used to validate identification numbers. For example, credit card numbers, IMEI numbers, National Provider Identifier numbers etc.
81. Create Keys with Function for Object
Write a JavaScript program to create an object with keys generated by running the provided function for each key. The object will have the same values as the provided object.
82. Map Array Values to Object
Write a JavaScript program to map array values to an object using a function. The key-value pairs consist of the original value as the key and the mapped value.
83. Map Characters of String to New String
Write a JavaScript program to create an updated string with the results of calling a provided function on every character in the called string.
84. Generate Object Values by Function
Write a JavaScript program to create an object with the same keys as the provided object. It will also generate values generated by running the provided function for each value.
85. Mask Characters Except Last Few
Write a JavaScript program to replace all but the last number of characters with the specified mask character.
86. Maximum Value of Array with Mapping
Write a JavaScript program to get the maximum value of an array, after mapping each element to a value using the provided function.
87. Get n Maximum Elements from Array
Write a JavaScript program to get the n maximum elements from the provided array. If n is greater than or equal to the provided array's length, return the original array (sorted in descending order).
88. Find Median of Numbers in Array
Write a JavaScript program to get the median of an array of numbers.
89. Negate Predicate Function
Write a JavaScript program to negates a predicate function.
90. Nest Flat Array Recursively
Write a JavaScript program to nest a given flat array of objects linked to one another recursively.
91. All Elements Fail Predicate Check
Write a JavaScript program that returns true if the provided predicate function returns false for all elements in a collection, false otherwise.
92. Get nth Argument by Index or Reverse Index
Write a JavaScript program to create a function that gets the argument at index n. If n is negative, the nth argument from the end is returned.
93. Remove Event Listener from Element
Write a JavaScript program to remove an event listener from an element.
94. Move Array Elements to End
Write a JavaScript program to move the specified amount of elements to the end of the array.
95. Add Event Listener with Delegation
Write a JavaScript program to add an event listener to an element with the ability to use event delegation.
96. Pick Keys from Object
Write a JavaScript program to pick the key-value pairs corresponding to the given keys from an object.
97. Object from Truthy Function Keys
Write a JavaScript program to create an object composed of the properties the given function returns truthy for. The function is invoked with two arguments: (value, key).
98. Filter Array of Objects by Condition
Write a JavaScript program to filter an array of objects based on a condition while also filtering out unspecified keys.
99. Hash String into Number
Write a JavaScript program to hash a given input string into a whole number.
100. Group Array by Index and Combine with Function
Write a JavaScript program to create an array of elements, grouped based on the position in the original arrays. Use function as the last value to specify how grouped values should be combined.
101. Object with Array Properties and Values
Write a JavaScript program to return the object associating the properties to the values of a given array of valid property identifiers and an array of values.
102. Group Array Elements by Position
Write a JavaScript program to create an array of elements, grouped based on the position in the original array.
103. String to Array of Words
Write a JavaScript program to convert a given string into an array of words.
104. Conditional Function Application
Write a JavaScript program to test a value, x, against a predicate function. If true, return fn(x). Else, return x.
105. Check if Value is a Number
Write a JavaScript program that returns true if the given value is a number, false otherwise.
106. Ungroup Array with Function
Write a JavaScript program to create an array of elements, ungrouping the elements in an array produced by zip and applying the provided function.
107. Distinct Values (Right-Side) by Comparator
Write a JavaScript program to get all distinct values (from the right side of the array) of an array, based on a provided comparator function.
108. Unique Values by Comparator
Write a JavaScript program to get all unique values of an array, based on a provided comparator function.
109. Get nth Element from Array
Write a JavaScript program to get the nth element of a given array.
110. All Elements from Two Arrays
Write a JavaScript program to get every element in any of the two arrays at once.
111. Build Array with Iterator and Seed
Write a JavaScript program to build an array, using an iterator function and an initial seed value.
112. Unflatten Object from Key Paths
Write a JavaScript program to unflatten an object with the paths for keys.
113. Unescape HTML Characters
Write a JavaScript program to unescape escaped HTML characters.
114. Uncurry Function to Depth n
Write a JavaScript program to uncurry a function up to depth n.
115. Single-Argument Function
Write a JavaScript program to create a function that accepts up to one argument, ignoring any additional arguments.
116. Truthy Predicate Check on Collection
Write a JavaScript program to check if the predicate (second argument) is truthy on all elements of a collection (first argument).
117. Truncate String to Length
Write a JavaScript program to truncate a string up to a specified length.
118. Reduce Object with Accumulator Function
Write a JavaScript program to apply a function against an accumulator and each key in the object (from left to right).
119. String for Tomorrow's Date
Write a JavaScript program to create tomorrow's date in a string representation.
120. String to Snake Case
Write a JavaScript program to convert a string to snake case.
121. Convert Value to Safe Integer
Write a JavaScript program to convert a value to a safe integer.
122. Add Ordinal Suffix to Number
Write a JavaScript program to add an ordinal suffix to a number.
123. String to Kebab Case
Write a JavaScript program to convert a string to kebab case.
124. Reduce Array-Like to Hash Map
Write a JavaScript program to reduce a given Array-like into a value hash (keyed data store).
125. Decimal Format Float to Comma-Separated String
Write a JavaScript program that converts float-point arithmetic to decimal form, and creates a comma separated string from a number.
126. Format Number as Currency
Write a JavaScript program to create a specified currency format from a given number.
127. Iterate Callback n Times
Write a JavaScript program to Iterate over a callback n times.
128. Remove Elements Until Function True
Write a JavaScript program to get removed elements of a given array until the passed function returns true.
129. Remove Elements from End Until True
Write a JavaScript program to get removed elements from the end of a given array until the passed function returns true.
130. Remove n Elements from End
Write a JavaScript program to remove n elements from the end of a given array.
131. Remove n Elements from Beginning
Write a JavaScript program to get an array with n elements removed from the beginning from a given array
132. Symmetric Difference with Comparator
Write a JavaScript program to get the symmetric difference between two given arrays, using a provided function as a comparator.
133. Symmetric Difference with Mapping
Write a JavaScript program to get the symmetric difference between two given arrays, after applying the provided function to each array element of both.
134. Symmetric Difference Between Arrays
Write a JavaScript program to get the symmetric difference between two given arrays.
135. Sum of Powers in Range
Write a JavaScript program to get the sum of the powers of all the numbers from start to end (both inclusive).
136. String Permutations (With Duplicates)
Write a JavaScript program to generate all permutations of a string (contains duplicates).
137. Stable Sort Array
Write a JavaScript program to perform stable sorting of an array, preserving the initial indexes of items when their values are the same. Returns a new array instead of mutating the original array.
138. Variadic Function with Array Inputs
Write a JavaScript program that takes a variadic function and returns a closure that accepts an array of arguments to map to the inputs of the function.
139. Split Multiline String to Array
Write a JavaScript program to split a multiline string into an array of lines.
140. Highest Index for Sorted Insertion (With Iterator)
Write a JavaScript program to get the highest index at which value should be inserted into an array in order to maintain its sort order. This is based on a provided iterator function.
141. Highest Index for Sorted Insertion
Write a JavaScript program to get the highest index at which value should be inserted into an array in order to maintain its sort order.
142. Lowest Index for Sorted Insertion
Write a JavaScript program to get the lowest index at which values should be inserted into an array in order to maintain its sorting order.
143. Sort String Alphabetically
Write a JavaScript program to sort the characters of a string Alphabetically.
144. Intersection of Two Arrays
Write a JavaScript program to get an array of elements that appear in both arrays.
145. Randomize Array Values
Write a JavaScript program to randomize the order of array values, returning an updated array.
146. Shallow Clone Object
Write a JavaScript program to create a shallow clone of an object.
147. Serialize Cookie Name-Value to Set-Cookie Header
Write a JavaScript program to serialize a cookie name-value pair into a Set-Cookie header string.
148. Hash String to Whole Number
Write a JavaScript program to hash the input string into a whole number.
149. Random Element from Array
Write a JavaScript program to get a random element from an array.
150. Run Promises in Series
Write a JavaScript program to run a given array of promises in series.
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