isxxxx

Lightweight library for checking number properties and mathematical classifications.

Installation

npm install isxxxx
# or
yarn add isxxxx
# or
pnpm add isxxxx

Usage

// Import specific functions
const { isEven, isPrime, isHappy } = require('isxxxx');

// Or import everything
const isxxxx = require('isxxxx');

// Examples
isEven(4);        // true
isPrime(17);      // true
isFibonacci(8);   // true
isHappy(19);      // true

Available Functions

Basic Properties

• isEven(num) - Checks if number is even
• isOdd(num) - Checks if number is odd
• isPositive(num) - Checks if number is positive
• isNegative(num) - Checks if number is negative
• isZero(num) - Checks if number is zero
• isInteger(num) - Checks if number is an integer
• isSafeInteger(num) - Checks if number is a safe integer in JavaScript
• isInRange(num, min, max) - Checks if number is within range (inclusive)

Mathematical Properties

• isPrime(num) - Checks if number is prime
• isPerfectSquare(num) - Checks if number is a perfect square
• isMultipleOf(num, multiple) - Checks if number is a multiple of another
• isPowerOfTwo(num) - Checks if number is a power of two
• isPowerOf(num, base) - Checks if number is a power of a given base
• isSquareFree(num) - Checks if number has no squared prime factors

Special Sequences

• isFibonacci(num) - Checks if number is in the Fibonacci sequence
• isLucas(num) - Checks if number is in the Lucas sequence
• isCatalan(num) - Checks if number is a Catalan number
• isBell(num) - Checks if number is a Bell number
• isTriangular(num) - Checks if number is triangular (1+2+3+...)
• isPentagonal(num) - Checks if number is pentagonal
• isHexagonal(num) - Checks if number is hexagonal
• isFactorial(num) - Checks if number is a factorial (n!)
• isRepunit(num) - Checks if number consists only of 1s
• isPronic(num) - Checks if number is pronic (n*(n+1))

Named Numbers

• isMersennePrime(num) - Checks if number is a Mersenne prime (2^n-1)
• isFermat(num) - Checks if number is a Fermat number (2^(2^n)+1)
• isCullen(num) - Checks if number is a Cullen number (n*2^n+1)
• isWoodall(num) - Checks if number is a Woodall number (n*2^n-1)
• isKaprekar(num) - Checks if number is a Kaprekar number
• isArmstrong(num) - Checks if number equals sum of its digits each raised to power of number of digits
• isNarcissistic(num) - Alias for isArmstrong
• isHappy(num) - Checks if a number is "happy" (process leads to 1)
• isHarshad(num) - Checks if number is divisible by sum of its digits
• isSmith(num) - Checks if digit sum equals digit sum of prime factors
• isApocalyptic(num) - Checks if 2^n contains "666"

Number Classifications

• isPerfect(num) - Checks if number equals sum of its proper divisors
• isAbundant(num) - Checks if number is less than sum of proper divisors
• isDeficient(num) - Checks if number is greater than sum of proper divisors
• isPowerful(num) - Checks if all prime factors also divide as squares
• isPractical(num) - Checks if every smaller number is sum of distinct divisors
• isSelfNumber(num) - Checks if number cannot be generated as n+sum(digits(n))
• isAutomorphic(num) - Checks if square ends with the number itself
• isPalindrome(num) - Checks if number reads the same forward and backward
• isAlternating(num) - Checks if digits alternate between odd and even
• isUndulant(num) - Checks if digits rise and fall alternately
• isCarmichael(num) - Checks if number satisfies Fermat's little theorem

Error Handling

All functions validate inputs and throw appropriate errors:

// Throws TypeError: Expected a number
isEven('not a number');

// Throws TypeError: Expected numbers
isMultipleOf('ten', 5);

// Throws Error: Cannot check for multiples of zero
isMultipleOf(10, 0);

License

MIT © Alexander KOP