Library

easy
Date Set UTC Seconds
Write a function that accepts a date object and a number of seconds (0 - 59) and returns a new date object with the seconds set to the provided value. The operation should be done using the setUTCSeconds() method.
easy
Search for Substring Kata
Create a function to search for a substring in a given string using String.prototype.search() method.
easy
String repeat Kata
Create a function that receives a string and a number as parameters. The function should return the string repeated `n` times, where n is the number passed as parameter.
easy
String.charAt() Kata
Write a function that accepts a string and a number as arguments, then returns the character at that position in the string. Use String.prototype.charAt() for this exercise.
medium
Precision Cutting Challenge
Write a function that can take in a list of numbers and precision cut them to a desired number of decimal places.
easy
String includes kata
Implement a function that takes an array of strings and a search string, and returns a new array containing only the strings that includes the search string using String.prototype.includes() method.
easy
Concatenate Strings
Create a function that takes two strings as input and concatenates them using the String.prototype.concat() method.
medium
String Normalization Kata
Create a function that receives a string and normalizes it using the String.prototype.normalize() method. Apply the NFC normalization form.
easy
Pad Start Kata
Create a function that takes in a string and a length and returns a new string with the original string padded with leading spaces if it is shorter than the provided length.
easy
String Padding Kata
Create a function that takes a string and a number and pads that string with a specified character until it reaches the given length.
medium
Date ToString Kata
Implement a function that takes a Date object as input and returns a formatted string
easy
Date Time Conversion
Converts a given date to a time string
easy
Set Milliseconds Kata
Implement a function that sets the milliseconds of a given date object to a specified value.
medium
Slice and Dice
Use Array.prototype.slice() to solve the following tasks.
easy
Set Add Kata
Implement a function that adds a value to a set using Set.prototype.add().
easy
String IndexOf Kata
Create a function that takes two parameters: a string and a target substring, and returns the index of the first occurrence of the target substring in the string. If the target substring is not found, return -1.
easy
Sum of numbers using reduceRight()
Write a function that takes an array of numbers and returns their sum, using Array.prototype.reduceRight().
easy
String padding kata
Create a function that takes a string and a number as arguments, and pads the string on the right side with spaces until the string reaches the desired length.
easy
UTC Date Converter
Write a function that takes a date string as input and converts it to a UTC date string format.
easy
CharAt Kata
Implement a function that returns the character at the specified index of a given string.
easy
Array Includes Kata
Write a function that checks if an element is present in an array using Array.prototype.includes() method.
medium
String Replace All Kata
Create a function that uses the String.prototype.replaceAll() method to replace all occurrences of a given substring within a string.
easy
Array Index Of Kata
Write a function that returns the index of the first occurrence of a given element in an array using Array.prototype.indexOf(). If the element is not found in the array, return -1.
medium
String Match Kata
Create a function that takes in a string and uses String.prototype.match() to find all occurrences of a pattern within the string.
easy
Set Keys Kata
Write a function that takes a Set object as a parameter and returns an array of keys using Set.prototype.keys().
easy
Replace First Occurrence of String
Write a function that replaces the first occurrence of a specific string in a given string.
easy
Array Concat Kata
Combine two arrays into a single array using the Array.prototype.concat() method
easy
String to Uppercase
Write a function that converts a given string to uppercase
medium
Array with() method
Implement the Array.prototype.with() method that returns a new array with the elements from the original array and the added elements.
easy
Substring Kata
Write a function that returns a substring of a given string, based on the start and end index provided
easy
Lowercase Kata
Write a function that takes a string and returns it in lowercase using the toLocaleLowerCase() method.
easy
Get UTC Seconds
Write a function that takes in a date and returns the seconds within the minute in UTC time.
easy
String IndexOf Kata
This kata focuses on using String.prototype.indexOf() method.
medium
Array Slice Kata
Implement various functionalities using Array.prototype.slice() method
easy
String Replace All
Create a function that replaces all occurrences of a substring with a new string.
medium
Date toLocaleTimeString() kata
Write a function that takes a Date object and returns a string representing the time portion of the date in the current time zone using the toLocaleTimeString() method. The function should also take an optional argument specifying the locale to use.
easy
Date.prototype.getYear() Kata
Write a function that takes a date and returns the year in the hh:mm:ss format.
easy
Get Day of Week from a Date
Write a function that uses the Date.prototype.getDay() method to determine the day of the week for a given date object.
easy
Reversed Array
Create a function that takes an array as input and returns a new array with the elements in reversed order.
easy
Array to String Conversion
Convert an array to a string with comma-separated values. The input array can contain numbers, strings, objects, or arrays.
easy
Array Type Check
Write a function that checks if a given variable is an array. If it is an array, return true, otherwise return false.
easy
String trimStart() Method
Write a function that uses the String.prototype.trimStart() method to remove any whitespace characters from the beginning of a given string.
easy
Array toLocaleString Kata
Create a function that will return an array in a localized way using the toLocaleString method.
easy
Reduce numbers array
Given an array of numbers, use reduce method to obtain a single value that represents the sum of all numbers in the array.
easy
String Search Kata
Write a function that takes a string and a search term and returns the index of the first occurrence of the search term in the given string. If the search term is not present in the string, return -1.
medium
Slice Challenge
Write a function that takes a string and returns all its substrings of length 3 or greater. You must use String.prototype.slice() to achieve this.
medium
Precision Cutting Kata
Write a function that takes in a string and uses precision cutting to remove all occurrences of the letter 'e'. Return the resulting string.
medium
Recursive Fibonacci Sequence
Write a function that returns the nth number in the Fibonacci sequence using recursion.
easy
Array Filling Kata
Fill arrays with specific values using Array.prototype.fill()
easy
Find Last Index Kata
Write a function that takes an array and a value as arguments and returns the index of the last occurrence of that value in the array using Array.prototype.lastIndexOf(). If the value is not found, return -1.
easy
Substring Kata
Given a string, return a new string that is a substring of the original string. The substring should start at a specified index and continue until the end of the original string.
easy
String code point kata
Write a function that takes a string and returns an array of code points for each character in the string using String.prototype.codePointAt() method.
easy
Set Delete Kata
Create a function that accepts a Set and a value to remove, and returns the updated Set after deleting the value.
easy
Array Every
Create a function that uses Array.prototype.every() to check if all the elements in an array meet a certain condition.
easy
Date.toLocaleDateString() Kata
Write a function that takes a Date object and returns the date formatted in the user's local format using the toLocaleDateString() method.
easy
Word sorting
Sort an array of words based on their alphabetical order using String.prototype.localeCompare() method.
easy
String to Uppercase
Create a function that takes a string as input and returns the same string in uppercase letters using the `toString()` method of the String object.
easy
Trimming Strings
Implement a function that removes leading and trailing whitespace from a string using the String.prototype.trim() method.
easy
Uppercase String Transformation
Create a function that transforms a given string to uppercase, using String.prototype.toLocaleUpperCase()
medium
setYear() Method
Create a function that takes a year (YYYY) and returns the date object with its year set to the provided year.
easy
Every Check
Write a function that checks if every element in an array satisfies a given condition.
easy
Set forEach Kata
Write a function that loops through a Set using Set.prototype.forEach() method and returns an array containing the results of applying the provided function to each element.
easy
Normalize String Kata
Create a function that normalizes a string using String.prototype.normalize method.
easy
Code Point At
Convert a string to an array of Unicode code points using String.prototype.codePointAt() method.
easy
Anagram Checker
Create a function that determines if two strings are anagrams of each other.
easy
String PadStart Kata
Implement a function that uses String's padStart method to add leading zeros to a number string to ensure it always has a minimum length
easy
String CharAt Kata
Write a function that extracts a character from a string given an index using String.prototype.charAt()
easy
Clearing unused items from Set
Implement a function that removes all unused items in a Set collection
easy
Convert Date to JSON String
Create a function that takes a Date object and returns a JSON string of the date in ISO format.
easy
Date Month Kata
Implement a function that returns the current month from Date object using Date.prototype.getMonth()
medium
Set full year
Create a function that takes a date and a year as arguments and returns a new date with the year set to the specified value using Date.prototype.setFullYear().
easy
String.lastIndexOf() Kata
Create a function that uses the String.prototype.lastIndexOf() method to find the index of the last occurrence of a specified substring in a given string.
medium
Grouping Arrays to Map
Given an array of objects, group the objects based on a specific key and return a map object.
easy
Normalize String Kata
Write a function that normalizes a string using String.prototype.normalize().
easy
Sort names using localeCompare()
Given an array of person objects, sort them alphabetically by their last name using String.prototype.localeCompare().
easy
Reverse Array
Create a function that takes an array and reverse its order in place.
easy
Splitting Strings
Given a sentence, split it into an array of words using the String.prototype.split() method.
easy
Hourly Greeting
Create a function that greets the user depending on the current hour of the day.
easy
Array Values Kata
Create a function that returns an array of values of an array using the Array.prototype.values() method.
easy
String endsWith Kata
Create a function that checks if a given string ends with a specified suffix.
easy
Trim Ending Spaces
Write a function that takes a string and removes any trailing whitespace at the end of it using String.prototype.trimEnd().
medium
String MatchAll Kata
Write a function that takes a string and regular expression as inputs, and returns an array of all matches found using the String.matchAll() method.
easy
Match Me If You Can
Create a function that takes two parameters: a string and a regular expression. The function should return an array of all matches found in the string using the regular expression.
easy
Get UTC Month
Create a function that returns the month of a Date object in UTC time zone.
easy
String includes
Create a function that takes in two parameters, a string and a substring, and checks if the string includes the substring. Return a boolean value.
easy
UTC Date
Given a date, return the UTC date.
medium
String Replace All Kata
Create a function that replaces all instances of a given substring with another string within a larger string using String.prototype.replaceAll() method.
medium
Array Slice and Splice
Given an array of numbers and a start index, remove a certain number of elements from the array and replace them with new elements.
medium
MatchAll Kata
Write a function that takes a string and returns an array of matched patterns using String.prototype.matchAll().
medium
Find Last Index Kata
Write a function that finds the last index of a given element in an array using the Array.prototype.findLastIndex method.
medium
Music Genre Classification
Create a function that takes in an array of music tracks and returns an object with the count of each genre in the array
medium
Recursive Fibonacci
Write a function that takes an integer n and returns the nth Fibonacci number using recursion.
easy
Set Event Start Time
Create a function that takes a start time and an event duration and returns the end time of the event, using the Date.prototype.setHours() method to set the hours of the start time.
medium
Recursive Factorial Function
Write a function that uses recursion to calculate the factorial of a given positive integer.
easy
Date Year Calculator
Create a function that returns the current year using Date's built-in getFullYear method
easy
String Includes Kata
Write a function that checks if a given string includes a specific substring. Use String.prototype.includes() method.
easy
String to Uppercase kata
Convert a string to uppercase using String.prototype.toUpperCase();
easy
Last Occurrence of a Substring in a String
Write a function that takes a string and a substring as arguments, and finds the last occurrence of the substring in the string. If the substring is not found, return -1.
easy
Sort Alphabets with localeCompare()
Create a function that sorts an array of strings in alphabetical order using String.prototype.localeCompare()
easy
EndsWith Kata
Write a function that checks whether a given string ends with the specified suffix or not.