largestPrimeFactor.js

function largestPrimeFactor(number) {

  let divisor, largestDivisor = 2;

  while (number % 2 === 0){
    number = number / divisor;
  }

  divisor = 3;
  while (number > 1){
    while(number % divisor === 0){
      number = number/divisor;
      largestDivisor = divisor;
    }
    divisor += 2;
  }
  return largestDivisor;
}