logan-maths-utils/index.js

A simple utility package with random number generator, palindrome checker, prime finder and more.

// Random number between min and max
function randomNumber(min, max) {
  return Math.floor(Math.random() * (max - min + 1)) + min;
}

// Find largest number
function findLargest(arr) {
  return Math.max(...arr);
}

// Find smallest number
function findSmallest(arr) {
  return Math.min(...arr);
}

// Sum of array
function sumArray(arr) {
  return arr.reduce((a, b) => a + b, 0);
}

// Average of array
function averageArray(arr) {
  return arr.length ? sumArray(arr) / arr.length : 0;
}

// Factorial
function factorial(n) {
  if (n < 0) return null;
  return n <= 1 ? 1 : n * factorial(n - 1);
}

// Fibonacci (nth number)
function fibonacci(n) {
  if (n < 0) return null;
  if (n <= 1) return n;
  let a = 0, b = 1;
  for (let i = 2; i <= n; i++) {
    [a, b] = [b, a + b];
  }
  return b;
}

// Check palindrome (string/number)
function isPalindrome(val) {
  const str = val.toString();
  return str === str.split("").reverse().join("");
}

// Prime check
function isPrime(num) {
  if (num <= 1) return false;
  for (let i = 2; i * i <= num; i++) {
    if (num % i === 0) return false;
  }
  return true;
}

// Largest prime in array
function largestPrime(arr) {
  const primes = arr.filter(isPrime);
  return primes.length ? Math.max(...primes) : null;
}

// GCD (Euclidean algorithm)
function gcd(a, b) {
  while (b) [a, b] = [b, a % b];
  return a;
}

// LCM
function lcm(a, b) {
  return (a * b) / gcd(a, b);
}

// Reverse string
function reverseString(str) {
  return str.split("").reverse().join("");
}

// Count vowels
function countVowels(str) {
  return (str.match(/[aeiou]/gi) || []).length;
}

// Check anagram
function isAnagram(str1, str2) {
  const format = str => str.toLowerCase().replace(/[^a-z0-9]/g, "").split("").sort().join("");
  return format(str1) === format(str2);
}

module.exports = {
  randomNumber,
  findLargest,
  findSmallest,
  sumArray,
  averageArray,
  factorial,
  fibonacci,
  isPalindrome,
  isPrime,
  largestPrime,
  gcd,
  lcm,
  reverseString,
  countVowels,
  isAnagram
};