Library

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

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

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

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

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

Create a function that repeats a given string n times.

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

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

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

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

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

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

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

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

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

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.

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 a substring as arguments, and finds the last occurrence of the substring in the string. If the 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.

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.

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

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

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

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

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

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

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

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

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

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.

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

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

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 repeats the string the given number of times.

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

Write a function that returns an array of char codes from a string

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

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

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

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.

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

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

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 takes in a Set and returns an array of entries

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

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

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

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

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

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

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

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

Write a function that returns the result of a string match with a given pattern.

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.

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 takes an array and a value as arguments and adds the value to the beginning of the array using the unshift() method.

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

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

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

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 program that classifies music genres based on certain audio features

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

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

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 takes a Date object as input and returns a formatted string

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

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

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 counts the number of seconds in a given timestamp

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.

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

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

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

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

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

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

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

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

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')

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 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 takes two arrays as arguments and concatenates them into a new array using the Array.prototype.concat() 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.

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