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

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.

Write a function that takes in a string and uses precision cutting to remove all occurrences of the letter 'e'. Return the resulting string.

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

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.

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

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

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

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.

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

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 receives a Date object and returns the milliseconds that have elapsed since the start of the day.

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

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

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 if every element in an array satisfies a given condition.

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.

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

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

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

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

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 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.

Implement normalize method to format a string removing all the accents

Write a function that concatenates two strings using the String.prototype.concat() method.

Create a function that takes two strings as input and concatenates them using the String.prototype.concat() method.

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.

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.

Create a function that uses Array.prototype.every() to check if all the elements in an array meet a certain condition.

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.

Create a function that transforms a given string to uppercase, using String.prototype.toLocaleUpperCase()

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

Create a function that concatenates two strings using the String.prototype.concat() 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.

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

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

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

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().

Write a function that takes two arrays as arguments and concatenates them into a new array using the Array.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.

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

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

Write a function that takes a Date object and returns the date formatted in the user's local format using the toLocaleDateString() method.

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

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

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

Given a date, return the UTC date.

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

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.

Complete the functions provided to properly utilize the Date.now() method.

Write a function that takes a string and a substring, and returns the index of the first occurrence of the substring in the string. If the substring is not found in the string, return -1.

Write a function that checks if a given string includes a specific substring. Use String.prototype.includes() method.

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

Implement a function that replaces all instances of a specified substring in a given string.

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.

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.

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

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

Create a function that takes in an array of music tracks and returns an object with the count of each genre in the array

Given an array of person objects, sort them alphabetically by their last name using String.prototype.localeCompare().

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

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.

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().

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

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

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

Create a function to search for a substring in a given string using String.prototype.search() method.

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

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 repeats a given string n times.

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

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.

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

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

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

Write a function that takes an array of numbers and returns their sum, using Array.prototype.reduceRight().

Sort an array of words based on their alphabetical order using String.prototype.localeCompare() method.

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

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

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 takes a string and returns an array of the char codes for each character in the 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.

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

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

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.

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

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

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.

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.

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

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

Write a function that returns whether a given string ends with the provided suffix or not

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

Create a function that will return an array in a localized way using the toLocaleString method.

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

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.