Project Euler - Largest prime factor

largestPrimeFactor.js

function isPrime(n) {
  if (isNaN(n) || !isFinite(n) || n % 1 || n < 2) {
    return false;
  }
  if (n % 2== 0) {
    return (n == 2);
  }
  if (n % 3== 0) {
    return (n == 3);
  }
  var m = Math.sqrt(n);
  for (var i = 5; i <= m;i += 6) {
    if (n % i== 0) {
      return false;
    }
    if (n % (i + 2) == 0) {
      return false;
    }
  }
  return true;
}

function *getFactors(inputNumber) {
  'use strict';

  var smallFactor = 1;
  var largeFactor = inputNumber;

  while (smallFactor < largeFactor) {
    largeFactor = inputNumber / smallFactor;
    if (largeFactor % 1 === 0) {
      yield smallFactor;
    }
    smallFactor++;
  }
}

var largestPrimeFactor = 1;
var seed = 600851475143;
for (var factor of getFactors(seed)) {
  if (isPrime(factor) && largestPrimeFactor <= factor) {
    largestPrimeFactor = factor;
  }
}

console.log(largestPrimeFactor);