Write a function that reverses a string without using the built-in reverse() method.

Write a function that finds the largest number in an array without using Math.max().

Write a function to check if a given string is a palindrome (reads the same forwards and backwards). Ignore case and non-alphanumeric characters.

Write a function that removes duplicate values from an array and returns the unique elements.

Write a function that returns the first N numbers of the Fibonacci sequence.

Write a function that counts the frequency of each character in a string and returns it as an object.

Write a function that checks whether a given number is prime.

Write a function that returns the factorial of a non-negative integer.

Write a function that checks if a given number is an Armstrong number (sum of its own digits each raised to the power of the number of digits equals the number).

Write a function that swaps two variables without using a third temporary variable.

Write a function that capitalizes the first letter of every word in a sentence.

Write a function that returns the sum of all numbers in an array without using reduce().

Write a function that checks if two strings are anagrams of each other.

Write a function that returns an array containing only the even numbers from an input array, without using filter().

Write a function that converts a temperature from Celsius to Fahrenheit and vice versa.

Write a function that counts the number of vowels in a string.

Write a function that returns the second largest number in an array.

Write a function that checks whether a given year is a leap year.

Write a function that converts an array of key-value pairs into an object.

Write a function that returns the number of words in a sentence.