Code Kata Solutions - Persistent Bugger

recursive.js

const multiply = (a, b) => a * b;

const multiplyDigits = num => (
  String(num).split('').reduce(multiply)
);

const persistence = (num, count = 0) => {
  if (num < 10) {
    return count;
  }
  
  const multiplied = multiplyDigits(num);
  
  return persistence(multiplied, count + 1);
};

while-loop.js

const multiply = (a, b) => a * b;

const multiplyDigits = num => (
  String(num).split('').reduce(multiply)
);

const persistence = num => {
  let count = 0;
  
  while (num > 9) {
    count += 1;
    num = multiplyDigits(num);
  }
  
  return count;
};