Library

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 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.

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

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 replaces all instances of a specified substring in a given string.

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

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

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

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

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

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

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

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

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

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.

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

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

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 two arrays as arguments and concatenates them into a new array using the Array.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 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 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.

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

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 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.

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

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, and repeats the string the given number of times.

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

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.

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

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

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

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 checks if it starts with a given substring. Return a boolean indicating whether or not the string starts with the given substring.

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

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

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

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

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

Implement normalize method to format a string removing all the accents

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

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

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

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

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

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

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

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

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

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

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

Given a date, return the UTC date.

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

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

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

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

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

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.

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

Converts a given date to a time string

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 sets the milliseconds of a given date object to a specified value.

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

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

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.

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

Sort an array of words based on their alphabetical order using String.prototype.localeCompare() 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 accepts a Set and a value to remove, and returns the updated Set after deleting the value.

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

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

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

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

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

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

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

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

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

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.

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

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

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

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.

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

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