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

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

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

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

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 sorts an array of strings in alphabetical order using String.prototype.localeCompare()

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

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

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.

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.

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

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 string as input and returns the same string in uppercase letters using the `toString()` method of the String object.

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

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

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

Given a date, return the UTC date.

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 it in lowercase using the toLocaleLowerCase() method.

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

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

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

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 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.

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

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

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 repeats a given string n times.

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

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

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

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

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.

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

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

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.

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.

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

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

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

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

Create a function that takes a date and a year and sets the date's UTC full year to the provided year.

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

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

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

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

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 all unused items in a Set collection

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

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 returns the current year using Date's built-in getFullYear 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 a string and returns an array of the char codes for each character in the string

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 a string as input and returns the string in all lowercase letters.

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

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

Write a function that can take in a list of numbers and precision cut them to a desired number of decimal places.

Create a function that replaces all instances of a given substring with another string within a larger string using String.prototype.replaceAll() method.

Implement normalize method to format a string removing all the accents

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 string as input and returns it in lower case.

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

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 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.

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.

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

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 in an array of music tracks and returns an object with the count of each genre in the array

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

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

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

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

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.

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

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

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

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 an array and reverse its order in place.

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

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

Write a function that converts a given string to uppercase

Combine two arrays into a single array using the Array.prototype.concat() method

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

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

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

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

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.

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.

Complete the functions to find the index of an element in an array using Array.prototype.indexOf().

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 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.

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