Library

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.

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.

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.

Convert an array to a string with comma-separated values. The input array can contain numbers, strings, objects, or arrays.

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

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

Given an array of numbers and a start index, remove a certain number of elements from the array and replace them with new elements.

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

Implement a function that checks if all elements from an array are included in a given Set using the built-in Set.prototype.has() method.

Create a function that takes an array and removes a portion of the array, as specified by the arguments, and returns the removed portion.

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

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

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.

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

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

Write a function that checks if every element in an array satisfies a given condition.

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

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.

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

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

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 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.

Create a function that takes in a string with extra white space at the beginning and end of the string, and returns a new string with that white space removed. Use String.prototype.trim().

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

Write a function that returns the nth number in the Fibonacci sequence using recursion.

Implement a function that concatenates a given string 'n' times using the String.prototype.repeat() method.

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.

Implement a function that groups an array of objects by a given key and returns a new array of objects, where each object has a key and an array of objects that have that key.

Write a function that converts a given string to uppercase

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

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

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

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 checks if a given variable is an array. If it is an array, return true, otherwise return false.

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

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

Implement equations using the Array.of() method to create arrays.

Given an array of objects, group the objects based on a specific key and return a map object.

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

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

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.

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().

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.

Write a function that takes an array and a value and pushes the value to the end of the array using Array.prototype.push().

Write a function that flattens nested arrays using Array.prototype.flat() method.

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

Fill arrays with specific values using Array.prototype.fill()

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

Write a function that checks if a given string has a unicode character code point greater than or equal to 128. Use the String.prototype.codePointAt() method.

Write a function that takes a date string as input and converts it to a UTC date string format.

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.

Create a function that slices a string based on a given start and end indexes

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.

Converts a given date to a time string

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

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

Create a function that returns the current minutes.

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

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 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().

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 concatenates two strings using the String.prototype.concat() method.

Write a function that takes a date object and a number representing the desired month, and sets the month of the date to the given month.

Given a sentence, split it into an array of words using the String.prototype.split() method.

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.

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

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

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.

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.

Given a date, return the UTC date.

Create a function that sorts an array of strings in alphabetical order using String.prototype.localeCompare()

Create a function that replaces all occurrences of a substring with a new string.

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 removes white space at the end of a given string using String.prototype.trimEnd().

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

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

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

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

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 takes in two parameters, a string and a substring, and checks if the string includes the substring. Return a boolean value.

Convert a string to uppercase using String.prototype.toUpperCase();

Create a function that returns an array of values of an array using the Array.prototype.values() method.

Implement the Array.prototype.with() method that returns a new array with the elements from the original array and the added elements.

Implement an algorithm that manages the overbooking of an airline flight.

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

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.

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

A kata that requires the student to use String.prototype.split() to split a given string into substrings and perform a specified operation on them.

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

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

Create a function that accepts a Set and a value to remove, and returns the updated Set after deleting the value.

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.

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

Use Array.prototype.slice() to solve the following tasks.

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 takes a date and returns the year in the hh:mm:ss format.

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

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