Library

Create a program that classifies music genres based on certain audio features

Write a function that checks if an element is present in an array using Array.prototype.includes() method.

Create a function that returns the month of a Date object in UTC time zone.

Create a function that takes an array as input and returns a new array with the elements in reversed order.

Write a function that returns the result of a string match with a given pattern.

Create a function that takes a string and a number and pads that string with a specified character until it reaches the given length.

Replace all vowels in a string with a '-'.

Implement a function that takes a Date object and a number representing minutes and sets the UTC minutes of the Date object to the provided value. The function should return the updated Date object.

Implement the Array.prototype.unshift() method without using built-in functions

Converts a given date to a time string

Create a function that normalizes a string using String.prototype.normalize method.

Write a function that takes a string and returns it in lowercase using the toLocaleLowerCase() method.

This kata focuses on using String.prototype.indexOf() method.

Implement a function that takes a string as input and returns it in lower case.

Implement a function that takes in a Set and returns an array of entries

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.

Write a function that takes a date object and a number of seconds and returns a new date object with the seconds set to the provided value. Example input: setSeconds(new Date('2022-10-10T10:10:10'), 30) Expected output: new Date('2022-10-10T10:10:30')

Implement a function that returns true if a given string starts with a specific substring.

Create a function that takes a string and returns an array of the char codes for each character in the string

Implement a function that adds a value to a set using Set.prototype.add().

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.

Create a function that checks if a given string ends with a specified suffix.

Create a function that takes a year (YYYY) and returns the date object with its year set to the provided year.

Write a function that uses the Date.prototype.getDay() method to determine the day of the week for a given date object.

Implement a function that takes a Date object as input and returns a formatted string

In this kata, you will be working with the String.prototype.toLocaleUpperCase() method to convert a string to uppercase according to the user's locale.

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.

Create a function that counts the number of seconds in a given timestamp

Create a function that takes a Date object and returns a JSON string of the date in ISO format.

Convert a string to an array of Unicode code points using String.prototype.codePointAt() method.

Write a function that uses the String.prototype.trimStart() method to remove any whitespace characters from the beginning of a given string.

Create a function that uses Array.prototype.findLast() to find the last element in an array that matches a given condition. Return the element if it exists or null if it does not.

Create a function that uses the String.prototype.replaceAll() method to replace all occurrences of a given substring within a string.

Write a function that takes two arrays as arguments and concatenates them into a new array using the Array.prototype.concat() method.

Create a function that repeats a given string n times.

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.

Create a function that searches for the last index of a substring in an array using Array.prototype.lastIndexOf().

Write a function that converts a given string to uppercase

Create a function that takes a string as input and returns the string in all lowercase letters.

Implement a function that groups the elements of an array based on a given predicate function.

Create a function that takes an array as input and returns an array of the keys of the given array using Array.prototype.keys() method.

Implement a function that removes all unused items in a Set collection

Given two arrays, join them to create a new array.

Write a function that joins two arrays into a single string using Array.prototype.join() method.

Create a function that accepts a string and a target length. If the length of the string is less than the target length, pad the string with spaces at the beginning until the target length is reached. If the string length is greater than or equal to the target length, return the original string.

Write a function that takes in a string and a target substring, and returns the index at which the target substring is first found. If the target substring is not found in the string, return -1. Use the built-in JavaScript method `indexOf()` to solve the problem.

Write a function that normalizes a string using String.prototype.normalize().

Implement normalize method to format a string removing all the accents

Write a function that returns the value of a given string using the String.prototype.valueOf() method.

Write a function that extracts a character from a string given an index using String.prototype.charAt()

Write a JavaScript function to find the index of an item in an array using Array.prototype.findIndex().

Create an Inventory Management System that allows users to add, remove and update items in the inventory.

Write a function that takes a string as input and splits it into an array of words using String.prototype.split(). Then, join the array back into a string using Array.prototype.join(). Finally, return the new string with a different delimiter separating each word.

Create a function that takes a string and returns a new string that is a slice of the original string. The function should take two arguments, start and end, which represent the starting and ending indices of the slice.

Write a function that takes a string and returns an array of matched patterns using String.prototype.matchAll().

Write a function that returns a substring of a given string, based on the start and end index provided

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.

Create a function that receives a string and a number n, the function should return the string repeated n times.

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.

Create a function that takes an array of numbers and returns the index of a given element. Use Array.prototype.findIndex() to implement the function.

Write a function that converts a given string to its string representation using the toString() method.

Write a function that takes in a date and returns the seconds within the minute in UTC time.

Create a function that returns the current date as a number (1-31).

Create a function that concatenates two strings using the String.prototype.concat() method. The function should take two string parameters and return the concatenated string.

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.

Write a function that returns an array of char codes from a string

Implement a function that uses String.prototype.trimEnd() to trim whitespace at the end of a string.

Create a function that sets the UTC month of a given date object.

Write a function that takes a Set object as a parameter and returns an array of keys using Set.prototype.keys().

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.

Write a function that takes a string and removes any trailing whitespace at the end of it using String.prototype.trimEnd().

Implement a function that returns the current month from Date object using Date.prototype.getMonth()

Create a function that greets the user depending on the current hour of the day.

Create a function that takes an array and a value as arguments and adds the value to the beginning of the array using the unshift() method.

Create a function that uses the copyWithin method to replace specified elements within an array.

Write a function that finds the last index of a given element in an array using the Array.prototype.findLastIndex method.

Given an array of numbers, use reduce method to obtain a single value that represents the sum of all numbers in the array.

Implement a function that returns the character at the specified index of a given string.

Write a function that takes a string and a regular expression and returns an array of all the substrings in the string that match the regular expression.

Write a function that replaces the first occurrence of a specific string in a given string.

Implement various functionalities using Array.prototype.slice() method

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.

Create a function that returns the current year using Date's built-in getFullYear method

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().

Create a Stock Advisor that recommends which stocks to buy based on certain parameters.

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.

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.

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.

Create a function that takes a string and a number, and repeats the string the given number of times.

Create a function that receives a string and normalizes it using the String.prototype.normalize() method. Apply the NFC normalization form.

Write a function that uses recursion to calculate the factorial of a given positive integer.

Write a function that returns a substring of a given string, starting at a specified index and ending before a specified index.

Write a function that checks whether a given string ends with the specified suffix or not.

Create a function that receives a string and a regular expression pattern and returns an array of all the occurrences of the pattern in the string using String.prototype.matchAll().

Implement a function that removes leading and trailing whitespace from a string using the String.prototype.trim() method.

Create a function that takes in a string and uses String.prototype.match() to find all occurrences of a pattern within the string.

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.

Create a function that uses Array.prototype.entries() to iterate over an array and perform some operations.

Create a function that takes in a string and checks if it starts with a given substring. Return a boolean indicating whether or not the string starts with the given substring.

Create a function that takes an array and reverse its order in place.