Library

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

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.

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.

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 string in all lowercase letters.

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

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

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

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

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

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

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

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

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

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 loops through a Set using Set.prototype.forEach() method and returns an array containing the results of applying the provided function to each element.

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

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

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

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.

Implement normalize method to format a string removing all the accents

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

Create a function that determines if two strings are anagrams of each other.

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 the result of a string match with a given pattern.

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

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

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

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

Create a function that receives a Date object and returns the milliseconds that have elapsed since the start 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.

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

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

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

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

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

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

Given a date, return the UTC date.

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

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

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

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

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

This kata focuses on using String.prototype.indexOf() 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 year using Date's built-in getFullYear method

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

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 normalizes a string using String.prototype.normalize().

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 will return an array in a localized way using the toLocaleString 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.

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

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

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')

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

Write a function that joins two arrays into a single string using Array.prototype.join() 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 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 to search for a substring in a given string using String.prototype.search() method.

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

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

Write a function that takes an integer n and returns the nth Fibonacci number using recursion.

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

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

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().

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

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.

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

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

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

Create a function that repeats a given string n times.

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

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

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

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.

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

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

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

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

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

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

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.

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

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

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

Converts a given date to a time string

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().