Library

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

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.

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

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

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.

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

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

Create a function that returns the current minutes.

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

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

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

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 replaces the first occurrence of a specific string in a given string.

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 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 a string and uses String.prototype.match() to find all occurrences of a pattern within the string.

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

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

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.

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

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 uses the String.prototype.replaceAll() method to replace all occurrences of a given substring within a string.

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.

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

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

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

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 checks if a given string ends with a specified suffix.

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

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

Given a date, return the UTC date.

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 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.

Converts a given date to a time string

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 converts a given string to uppercase

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 concatenates two strings using the String.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 takes a string and a number, and repeats the string the given number of times.

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

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

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

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

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

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

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

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

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

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

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

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().

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

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 returns the current month from Date object using Date.prototype.getMonth()

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

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

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

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 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.

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

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

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

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

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 takes a string and a regular expression and returns an array of all the substrings in the string that match the regular expression.

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

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

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

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

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.

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

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

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

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

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 returns the current date as a number (1-31).

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.

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

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 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.

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

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 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.

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

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

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 a string and a number as arguments, and pads the string on the right side with spaces until the string reaches the desired length.

Implement a function that removes leading and trailing whitespace from a string using the String.prototype.trim() 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.

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.