JSFiddle - React, Tailwind, and code Playground

by Anton Spirin

JavaScript

const persistence = (number, i = 0) => {
  const digits = number.toString().split('');
  const result = digits.reduce((acc, el) => acc * el);
 
  if(result > 9) {
    return persistence(result, ++i);
  }

  return ++i;
}

alert(persistence(999));